Purpose of This PDQ Summary
Overview
General Information
History
Laboratory/Animal/Preclinical Studies
Human/Clinical Studies
Adverse Effects
Overall Level of Evidence for Coenzyme Q₁₀
Changes to This Summary (12/18/2007)
More Information

Purpose of This PDQ Summary

This PDQ cancer information summary for health professionals provides comprehensive, peer-reviewed, evidence-based information about the use of coenzyme Q₁₀ as a treatment for cancer. The summary is reviewed regularly and updated as necessary by the PDQ Cancer Complementary and Alternative Medicine Editorial Board ¹.

Information about the following is included in this summary:

• A brief history of coenzyme Q₁₀ research.
• The results of clinical studies of coenzyme Q₁₀.
• Possible side effects of coenzyme Q₁₀ use.

This summary is intended as a resource to inform and assist clinicians and other health professionals who care for cancer patients. It does not provide formal guidelines or recommendations for making health care decisions.

Some of the reference citations in the summary are accompanied by a level of evidence designation. These designations are intended to help the readers assess the strength of the evidence supporting the use of specific interventions or treatment strategies. The PDQ Cancer Complementary and Alternative Medicine Editorial Board uses a formal evidence ranking system ² in developing its level of evidence designations. These designations should not be used as a basis for reimbursement determinations.

This summary is also available in a patient version ³, which is written in less technical language.

Overview

This complementary and alternative medicine (CAM) information summary provides an overview of the use of coenzyme Q₁₀ in cancer therapy. The summary includes a history of coenzyme Q₁₀ research, a review of laboratory studies, and data from investigations involving human subjects. Although several naturally occurring forms of coenzyme Q have been identified, Q₁₀ is the predominant form found in humans and most mammals, and it is the form most studied for therapeutic potential. Thus, it will be the only form of coenzyme Q discussed in this summary.

This summary contains the following key information:

• Coenzyme Q₁₀ is made naturally by the human body.
• Coenzyme Q₁₀ helps cells to produce energy, and it acts as an antioxidant.
• Coenzyme Q₁₀ has shown an ability to stimulate the immune system and to protect the heart from damage caused by certain chemotherapy drugs.
• Low blood levels of coenzyme Q₁₀ have been detected in patients with some types of cancer.
• No report of a randomized clinical trial of coenzyme Q₁₀ as a treatment for cancer has been published in a peer-reviewed, scientific journal.
• Coenzyme Q₁₀ is marketed in the United States as a dietary supplement.

Many of the medical and scientific terms used in the summary are hypertext linked (at first use in each section) to the NCI Dictionary ⁴, which is oriented toward nonexperts. When a linked term is clicked, a definition will appear in a separate window. All linked terms and their corresponding definitions will appear in a glossary in the printable version of the summary.

Reference citations in some PDQ CAM information summaries may include links to external Web sites that are operated by individuals or organizations for the purpose of marketing or advocating the use of specific treatments or products. These reference citations are included for informational purposes only. Their inclusion should not be viewed as an endorsement of the content of the Web sites or of any treatment or product by the PDQ Cancer CAM Editorial Board or the National Cancer Institute (NCI).

General Information

Coenzyme Q₁₀ (also known as CoQ₁₀, Q₁₀, vitamin Q₁₀, ubiquinone, and ubidecarenone) is a benzoquinone compound synthesized naturally by the human body. The “Q” and the “10” in the name refer to the quinone chemical group and the 10 isoprenyl chemical subunits, respectively, that are part of this compound’s structure. The term “coenzyme” denotes it as an organic (contains carbon atoms), nonprotein molecule necessary for the proper functioning of its protein partner (an enzyme or an enzyme complex). Coenzyme Q₁₀ is used by cells of the body in a process known variously as aerobic respiration, aerobic metabolism, oxidative metabolism, or cell respiration. Through this process, energy for cell growth and maintenance is created inside cells in compartments called mitochondria. Reviewed in [1-4] Coenzyme Q₁₀ is also used by the body as an endogenous antioxidant. Reviewed in [1,2,4-8] An antioxidant is a substance that protects cells from free radicals, which are highly reactive chemicals, often containing oxygen atoms, capable of damaging important cellular components such as DNA and lipids. In addition, the plasma level of coenzyme Q₁₀ has been used, in studies, as a measure of oxidative stress (a situation in which normal antioxidant levels are reduced).[9,10]

Coenzyme Q₁₀ is present in most tissues, but the highest concentrations are found in the heart, the liver, the kidneys, and the pancreas.[11] The lowest concentration is found in the lungs.[11] Tissue levels of this compound decrease as people age, due to increased requirements, decreased production,[11] or insufficient intake of the chemical precursors needed for synthesis. Reviewed in [12] In humans, normal blood levels of coenzyme Q₁₀ have been defined variably, with reported normal values ranging from 0.30 to 3.84 µg /mL.[13,14] Reviewed in [2,4]

Given the importance of coenzyme Q₁₀ to optimal cellular energy production, use of this compound as a treatment for diseases other than cancer has been explored. Most of these investigations have focused on coenzyme Q₁₀ as a treatment for cardiovascular disease.[15] Reviewed in [2,4] In patients with cancer, coenzyme Q₁₀ has been shown to protect the heart from anthracycline -induced cardiotoxicity (anthracyclines are a family of chemotherapy drugs, including doxorubicin, that have the potential to damage the heart)[3,16-18] and to stimulate the immune system.[19] Reviewed in [20] Stimulation of the immune system by this compound has also been observed in animal studies and in humans without cancer.[21-27] In part because of its immunostimulatory potential, coenzyme Q₁₀ has been used as an adjuvant therapy in patients with various types of cancer.[17,28-30] Reviewed in [20,31-33]

While coenzyme Q₁₀ may show indirect anticancer activity through its effect(s) on the immune system, there is evidence to suggest that analogs of this compound can suppress cancer growth directly. Analogs of coenzyme Q₁₀ have been shown to inhibit the proliferation of cancer cells in vitro and the growth of cancer cells transplanted into rats and mice.[12,34] In view of these findings, it has been proposed that analogs of coenzyme Q₁₀ may function as antimetabolites to disrupt normal biochemical reactions that are required for cell growth and/or survival and, thus, that they may be useful for short periods of time as chemotherapeutic agents.[12,34]

Several companies distribute coenzyme Q₁₀ as a dietary supplement. In the United States, dietary supplements are regulated as foods, not drugs. Therefore, premarket evaluation and approval by the U.S. Food and Drug Administration (FDA) are not required unless specific disease prevention or treatment claims are made. The FDA can, however, remove from the market dietary supplements that it deems unsafe. Because dietary supplements are not formally reviewed for manufacturing consistency, there may be considerable variation from lot to lot. The FDA has not approved coenzyme Q₁₀ for the treatment of cancer or any other medical condition.

To conduct clinical drug research in the United States, researchers must file an Investigational New Drug (IND) application with the FDA. The IND application process is highly confidential, and IND information can be disclosed only by the applicants. To date, no investigators have announced that they have applied for an IND to study coenzyme Q₁₀ as a treatment for cancer.

In animal studies, coenzyme Q₁₀ has been administered by injection (intravenous, intraperitoneal, intramuscular, or subcutaneous). In humans, it is usually taken orally as a pill (tablet or capsule), but intravenous infusions have been given.[4] Coenzyme Q₁₀ is absorbed best with fat; therefore, lipid preparations are better absorbed than the purified compound. Reviewed in [2,4] In human studies, supplementation doses and administration schedules have varied, but usually have been in the range of 90 to 390 mg/day.

References

1. Crane FL, Sun IL, Sun EE: The essential functions of coenzyme Q. Clin Investig 71 (8 Suppl): S55-9, 1993.  [PUBMED Abstract]
   
   
2. Pepping J: Coenzyme Q10. Am J Health Syst Pharm 56 (6): 519-21, 1999.  [PUBMED Abstract]
   
   
3. Folkers K, Wolaniuk A: Research on coenzyme Q10 in clinical medicine and in immunomodulation. Drugs Exp Clin Res 11 (8): 539-45, 1985.  [PUBMED Abstract]
   
   
4. Overvad K, Diamant B, Holm L, et al.: Coenzyme Q10 in health and disease. Eur J Clin Nutr 53 (10): 764-70, 1999.  [PUBMED Abstract]
   
   
5. Beyer RE, Nordenbrand K, Ernster L: The role of coenzyme Q as a mitochondrial antioxidant: a short review. In: Folkers K, Yamamura Y, eds.: Biomedical and Clinical Aspects of Coenzyme Q. Vol 5. Amsterdam, The Netherlands: Elsevier Science Publishers B V (Biomedical Division), 1986, pp 17-24. 
   
   
6. Gordon M: Dietary antioxidants in disease prevention. Nat Prod Rep 13 (4): 265-73, 1996.  [PUBMED Abstract]
   
   
7. Palazzoni G, Pucello D, Littarru GP, et al.: Coenzyme Q10 and colorectal neoplasms in aged patients. Rays 22 (1 Suppl): 73-6, 1997 Jan-Mar.  [PUBMED Abstract]
   
   
8. Ernster L, Dallner G: Biochemical, physiological and medical aspects of ubiquinone function. Biochim Biophys Acta 1271 (1): 195-204, 1995.  [PUBMED Abstract]
   
   
9. Yamamoto Y, Yamashita S, Fujisawa A, et al.: Oxidative stress in patients with hepatitis, cirrhosis, and hepatoma evaluated by plasma antioxidants. Biochem Biophys Res Commun 247 (1): 166-70, 1998.  [PUBMED Abstract]
   
   
10. Yamamoto Y, Yamashita S: Plasma ratio of ubiquinol and ubiquinone as a marker of oxidative stress. Mol Aspects Med 18 (Suppl): S79-84, 1997.  [PUBMED Abstract]
    
    
11. Ernster L, Forsmark-Andrée P: Ubiquinol: an endogenous antioxidant in aerobic organisms. Clin Investig 71 (8 Suppl): S60-5, 1993.  [PUBMED Abstract]
    
    
12. Folkers K: The potential of coenzyme Q 10 (NSC-140865) in cancer treatment. Cancer Chemother Rep 2 4 (4): 19-22, 1974.  [PUBMED Abstract]
    
    
13. Folkers K, Osterborg A, Nylander M, et al.: Activities of vitamin Q10 in animal models and a serious deficiency in patients with cancer. Biochem Biophys Res Commun 234 (2): 296-9, 1997.  [PUBMED Abstract]
    
    
14. Jolliet P, Simon N, Barré J, et al.: Plasma coenzyme Q10 concentrations in breast cancer: prognosis and therapeutic consequences. Int J Clin Pharmacol Ther 36 (9): 506-9, 1998.  [PUBMED Abstract]
    
    
15. Baggio E, Gandini R, Plancher AC, et al.: Italian multicenter study on the safety and efficacy of coenzyme Q10 as adjunctive therapy in heart failure. CoQ10 Drug Surveillance Investigators. Mol Aspects Med 15 (Suppl): s287-94, 1994.  [PUBMED Abstract]
    
    
16. Cortes EP, Gupta M, Chou C, et al.: Adriamycin cardiotoxicity: early detection by systolic time interval and possible prevention by coenzyme Q10. Cancer Treat Rep 62 (6): 887-91, 1978.  [PUBMED Abstract]
    
    
17. Folkers K, Brown R, Judy WV, et al.: Survival of cancer patients on therapy with coenzyme Q10. Biochem Biophys Res Commun 192 (1): 241-5, 1993.  [PUBMED Abstract]
    
    
18. Iarussi D, Auricchio U, Agretto A, et al.: Protective effect of coenzyme Q10 on anthracyclines cardiotoxicity: control study in children with acute lymphoblastic leukemia and non-Hodgkin lymphoma. Mol Aspects Med 15 (Suppl): s207-12, 1994.  [PUBMED Abstract]
    
    
19. Folkers K, Shizukuishi S, Takemura K, et al.: Increase in levels of IgG in serum of patients treated with coenzyme Q10. Res Commun Chem Pathol Pharmacol 38 (2): 335-8, 1982.  [PUBMED Abstract]
    
    
20. Complementary treatments highlighted at recent meeting. Oncology (Huntingt) 13 (2): 166, 1999.  [PUBMED Abstract]
    
    
21. Bliznakov E, Casey A, Premuzic E: Coenzymes Q: stimulants of the phagocytic activity in rats and immune response in mice. Experientia 26 (9): 953-4, 1970.  [PUBMED Abstract]
    
    
22. Folkers K, Hanioka T, Xia LJ, et al.: Coenzyme Q10 increases T4/T8 ratios of lymphocytes in ordinary subjects and relevance to patients having the AIDS related complex. Biochem Biophys Res Commun 176 (2): 786-91, 1991.  [PUBMED Abstract]
    
    
23. Kawase I, Niitani H, Saijo N, et al.: Enhancing effect of coenzyme, Q10 on immunorestoration with Mycobacterium bovis BCG in tumor-bearing mice. Gann 69 (4): 493-7, 1978.  [PUBMED Abstract]
    
    
24. Bliznakov EG: Effect of stimulation of the host defense system by coenzyme Q 10 on dibenzpyrene-induced tumors and infection with Friend leukemia virus in mice. Proc Natl Acad Sci U S A 70 (2): 390-4, 1973.  [PUBMED Abstract]
    
    
25. Bliznakov EG, Adler AD: Nonlinear response of the reticuloendothelial system upon stimulation. Pathol Microbiol (Basel) 38 (6): 393-410, 1972.  [PUBMED Abstract]
    
    
26. Bliznakov EG: Coenzyme Q in experimental infections and neoplasia. In: Folkers K, Yamamura Y, eds.: Biomedical and Clinical Aspects of Coenzyme Q. Vol 1. Amsterdam, The Netherlands: Elsevier/North-Holland Biomedical Press, 1977, pp 73-83. 
    
    
27. Barbieri B, Lund B, Lundström B, et al.: Coenzyme Q10 administration increases antibody titer in hepatitis B vaccinated volunteers--a single blind placebo-controlled and randomized clinical study. Biofactors 9 (2-4): 351-7, 1999.  [PUBMED Abstract]
    
    
28. Lockwood K, Moesgaard S, Hanioka T, et al.: Apparent partial remission of breast cancer in 'high risk' patients supplemented with nutritional antioxidants, essential fatty acids and coenzyme Q10. Mol Aspects Med 15 (Suppl): s231-40, 1994.  [PUBMED Abstract]
    
    
29. Lockwood K, Moesgaard S, Folkers K: Partial and complete regression of breast cancer in patients in relation to dosage of coenzyme Q10. Biochem Biophys Res Commun 199 (3): 1504-8, 1994.  [PUBMED Abstract]
    
    
30. Lockwood K, Moesgaard S, Yamamoto T, et al.: Progress on therapy of breast cancer with vitamin Q10 and the regression of metastases. Biochem Biophys Res Commun 212 (1): 172-7, 1995.  [PUBMED Abstract]
    
    
31. Folkers K: Relevance of the biosynthesis of coenzyme Q10 and of the four bases of DNA as a rationale for the molecular causes of cancer and a therapy. Biochem Biophys Res Commun 224 (2): 358-61, 1996.  [PUBMED Abstract]
    
    
32. Ren S, Lien EJ: Natural products and their derivatives as cancer chemopreventive agents. Prog Drug Res 48: 147-71, 1997.  [PUBMED Abstract]
    
    
33. Hodges S, Hertz N, Lockwood K, et al.: CoQ10: could it have a role in cancer management? Biofactors 9 (2-4): 365-70, 1999.  [PUBMED Abstract]
    
    
34. Folkers K, Porter TH, Bertino JR, et al.: Inhibition of two human tumor cell lines by antimetabolites of coenzyme Q10. Res Commun Chem Pathol Pharmacol 19 (3): 485-90, 1978.  [PUBMED Abstract]
    
    

History

Coenzyme Q₁₀ was first isolated in 1957, Reviewed in [1] and its chemical structure (benzoquinone compound) was determined in 1958. Reviewed in [2] Interest in coenzyme Q₁₀ as a therapeutic agent in cancer began in 1961, when a deficiency was noted in the blood of both Swedish and American cancer patients, especially in the blood of patients with breast cancer.[2] Reviewed in [3,4] A subsequent study showed a statistically significant relationship between the level of plasma coenzyme Q₁₀ deficiency and breast cancer prognosis.[5] Low blood levels of this compound have been reported in patients with malignancies other than breast cancer, including myeloma, lymphoma, and cancers of the lung, prostate, pancreas, colon, kidney, and head and neck.[2,6] Reviewed in [7] Furthermore, decreased levels of coenzyme Q₁₀ have been detected in malignant human tissue,[8-12] but increased levels have been reported as well.[8]

A large amount of laboratory and animal data on coenzyme Q₁₀ has accumulated since 1962. Reviewed in [2] Research into cellular energy-producing mechanisms that involve this compound was awarded the Nobel Prize in chemistry in 1978. Some of the accumulated data show that coenzyme Q₁₀ stimulates animal immune systems, leading to higher antibody levels,[13] greater numbers and/or activities of macrophages and T cells (T lymphocytes),[13,14] and increased resistance to infection.[15-17] Coenzyme Q₁₀ has also been reported to increase IgG (immunoglobulin G) antibody levels and to increase the CD4 to CD8 T-cell ratio in humans.[18-20] CD4 and CD8 are proteins found on the surface of T cells, with CD4 and CD8 identifying helper T cells and cytotoxic T cells, respectively; decreased CD4 to CD8 T-cell ratios have been reported for cancer patients.[21,22] Research subsequently delineated the antioxidant properties of coenzyme Q₁₀.[23,24] Reviewed in[25-27]

Proposed mechanisms of action for coenzyme Q₁₀ that are relevant to cancer include its essential function in cellular energy production and its stimulation of the immune system (which may both be related), as well as its role as an antioxidant. Coenzyme Q₁₀ is essential to aerobic energy production, Reviewed in [1,25,28] and it has been suggested that increased cellular energy leads to increased antibody synthesis in B cells (B lymphocytes).[6,18] As noted previously (General Information section ⁵), coenzyme Q₁₀ can also behave as an antioxidant. Reviewed in [1,25-27,29-32] In this capacity, coenzyme Q₁₀ is thought to stabilize cell membranes (lipid -containing structures essential to maintaining cell integrity) and to prevent free radical damage to other important cellular components. Reviewed in [1,25,27,32] Free radical damage to DNA (and possibly to other cellular molecules) may be a factor in cancer development. Reviewed in [11,23,30,33-36]

References

1. Pepping J: Coenzyme Q10. Am J Health Syst Pharm 56 (6): 519-21, 1999.  [PUBMED Abstract]
   
   
2. Folkers K, Osterborg A, Nylander M, et al.: Activities of vitamin Q10 in animal models and a serious deficiency in patients with cancer. Biochem Biophys Res Commun 234 (2): 296-9, 1997.  [PUBMED Abstract]
   
   
3. Lockwood K, Moesgaard S, Yamamoto T, et al.: Progress on therapy of breast cancer with vitamin Q10 and the regression of metastases. Biochem Biophys Res Commun 212 (1): 172-7, 1995.  [PUBMED Abstract]
   
   
4. Ren S, Lien EJ: Natural products and their derivatives as cancer chemopreventive agents. Prog Drug Res 48: 147-71, 1997.  [PUBMED Abstract]
   
   
5. Jolliet P, Simon N, Barré J, et al.: Plasma coenzyme Q10 concentrations in breast cancer: prognosis and therapeutic consequences. Int J Clin Pharmacol Ther 36 (9): 506-9, 1998.  [PUBMED Abstract]
   
   
6. Folkers K: The potential of coenzyme Q 10 (NSC-140865) in cancer treatment. Cancer Chemother Rep 2 4 (4): 19-22, 1974.  [PUBMED Abstract]
   
   
7. Folkers K: Relevance of the biosynthesis of coenzyme Q10 and of the four bases of DNA as a rationale for the molecular causes of cancer and a therapy. Biochem Biophys Res Commun 224 (2): 358-61, 1996.  [PUBMED Abstract]
   
   
8. Chipperfield B: Ubiquinone concentrations in some tumour-bearing tissues. Ubiquinone concentrations in tumours and some normal tissues in man. Nature 209 (29): 1207-8, 1966.  [PUBMED Abstract]
   
   
9. Eggens I, Elmberger PG, Löw P: Polyisoprenoid, cholesterol and ubiquinone levels in human hepatocellular carcinomas. Br J Exp Pathol 70 (1): 83-92, 1989.  [PUBMED Abstract]
   
   
10. Mano T, Iwase K, Hayashi R, et al.: Vitamin E and coenzyme Q concentrations in the thyroid tissues of patients with various thyroid disorders. Am J Med Sci 315 (4): 230-2, 1998.  [PUBMED Abstract]
    
    
11. Picardo M, Grammatico P, Roccella F, et al.: Imbalance in the antioxidant pool in melanoma cells and normal melanocytes from patients with melanoma. J Invest Dermatol 107 (3): 322-6, 1996.  [PUBMED Abstract]
    
    
12. Portakal O, Ozkaya O, Erden Inal M, et al.: Coenzyme Q10 concentrations and antioxidant status in tissues of breast cancer patients. Clin Biochem 33 (4): 279-84, 2000.  [PUBMED Abstract]
    
    
13. Bliznakov E, Casey A, Premuzic E: Coenzymes Q: stimulants of the phagocytic activity in rats and immune response in mice. Experientia 26 (9): 953-4, 1970.  [PUBMED Abstract]
    
    
14. Kawase I, Niitani H, Saijo N, et al.: Enhancing effect of coenzyme, Q10 on immunorestoration with Mycobacterium bovis BCG in tumor-bearing mice. Gann 69 (4): 493-7, 1978.  [PUBMED Abstract]
    
    
15. Bliznakov EG: Effect of stimulation of the host defense system by coenzyme Q 10 on dibenzpyrene-induced tumors and infection with Friend leukemia virus in mice. Proc Natl Acad Sci U S A 70 (2): 390-4, 1973.  [PUBMED Abstract]
    
    
16. Bliznakov EG, Adler AD: Nonlinear response of the reticuloendothelial system upon stimulation. Pathol Microbiol (Basel) 38 (6): 393-410, 1972.  [PUBMED Abstract]
    
    
17. Bliznakov EG: Coenzyme Q in experimental infections and neoplasia. In: Folkers K, Yamamura Y, eds.: Biomedical and Clinical Aspects of Coenzyme Q. Vol 1. Amsterdam, The Netherlands: Elsevier/North-Holland Biomedical Press, 1977, pp 73-83. 
    
    
18. Folkers K, Shizukuishi S, Takemura K, et al.: Increase in levels of IgG in serum of patients treated with coenzyme Q10. Res Commun Chem Pathol Pharmacol 38 (2): 335-8, 1982.  [PUBMED Abstract]
    
    
19. Folkers K, Hanioka T, Xia LJ, et al.: Coenzyme Q10 increases T4/T8 ratios of lymphocytes in ordinary subjects and relevance to patients having the AIDS related complex. Biochem Biophys Res Commun 176 (2): 786-91, 1991.  [PUBMED Abstract]
    
    
20. Barbieri B, Lund B, Lundström B, et al.: Coenzyme Q10 administration increases antibody titer in hepatitis B vaccinated volunteers--a single blind placebo-controlled and randomized clinical study. Biofactors 9 (2-4): 351-7, 1999.  [PUBMED Abstract]
    
    
21. Shaw M, Ray P, Rubenstein M, et al.: Lymphocyte subsets in urologic cancer patients. Urol Res 15 (3): 181-5, 1987.  [PUBMED Abstract]
    
    
22. Tsuyuguchi I, Shiratsuchi H, Fukuoka M: T-lymphocyte subsets in primary lung cancer. Jpn J Clin Oncol 17 (1): 13-7, 1987.  [PUBMED Abstract]
    
    
23. Yamamoto Y, Yamashita S, Fujisawa A, et al.: Oxidative stress in patients with hepatitis, cirrhosis, and hepatoma evaluated by plasma antioxidants. Biochem Biophys Res Commun 247 (1): 166-70, 1998.  [PUBMED Abstract]
    
    
24. Yamamoto Y, Yamashita S: Plasma ratio of ubiquinol and ubiquinone as a marker of oxidative stress. Mol Aspects Med 18 (Suppl): S79-84, 1997.  [PUBMED Abstract]
    
    
25. Crane FL, Sun IL, Sun EE: The essential functions of coenzyme Q. Clin Investig 71 (8 Suppl): S55-9, 1993.  [PUBMED Abstract]
    
    
26. Overvad K, Diamant B, Holm L, et al.: Coenzyme Q10 in health and disease. Eur J Clin Nutr 53 (10): 764-70, 1999.  [PUBMED Abstract]
    
    
27. Ernster L, Forsmark-Andrée P: Ubiquinol: an endogenous antioxidant in aerobic organisms. Clin Investig 71 (8 Suppl): S60-5, 1993.  [PUBMED Abstract]
    
    
28. Folkers K, Wolaniuk A: Research on coenzyme Q10 in clinical medicine and in immunomodulation. Drugs Exp Clin Res 11 (8): 539-45, 1985.  [PUBMED Abstract]
    
    
29. Beyer RE, Nordenbrand K, Ernster L: The role of coenzyme Q as a mitochondrial antioxidant: a short review. In: Folkers K, Yamamura Y, eds.: Biomedical and Clinical Aspects of Coenzyme Q. Vol 5. Amsterdam, The Netherlands: Elsevier Science Publishers B V (Biomedical Division), 1986, pp 17-24. 
    
    
30. Gordon M: Dietary antioxidants in disease prevention. Nat Prod Rep 13 (4): 265-73, 1996.  [PUBMED Abstract]
    
    
31. Palazzoni G, Pucello D, Littarru GP, et al.: Coenzyme Q10 and colorectal neoplasms in aged patients. Rays 22 (1 Suppl): 73-6, 1997 Jan-Mar.  [PUBMED Abstract]
    
    
32. Ernster L, Dallner G: Biochemical, physiological and medical aspects of ubiquinone function. Biochim Biophys Acta 1271 (1): 195-204, 1995.  [PUBMED Abstract]
    
    
33. Aust AE, Eveleigh JF: Mechanisms of DNA oxidation. Proc Soc Exp Biol Med 222 (3): 246-52, 1999.  [PUBMED Abstract]
    
    
34. Halliwell B: Oxygen and nitrogen are pro-carcinogens. Damage to DNA by reactive oxygen, chlorine and nitrogen species: measurement, mechanism and the effects of nutrition. Mutat Res 443 (1-2): 37-52, 1999.  [PUBMED Abstract]
    
    
35. Burcham PC: Internal hazards: baseline DNA damage by endogenous products of normal metabolism. Mutat Res 443 (1-2): 11-36, 1999.  [PUBMED Abstract]
    
    
36. Dreher D, Junod AF: Role of oxygen free radicals in cancer development. Eur J Cancer 32A (1): 30-8, 1996.  [PUBMED Abstract]
    
    

Laboratory/Animal/Preclinical Studies

Laboratory work on coenzyme Q₁₀ has focused primarily on its structure and its function in cell respiration. Studies in animals have demonstrated that coenzyme Q₁₀ is capable of stimulating the immune system, with treated animals showing increased resistance to protozoal infections [1,2] and to viral and chemically induced neoplasia.[1-3] Reviewed in [4] Early studies of coenzyme Q₁₀ showed increased hematopoiesis (the formation of new blood cells) in monkeys, Reviewed in [4,5] rabbits,[6] and poultry. Reviewed in [5] Coenzyme Q₁₀ demonstrated a protective effect on the heart muscle of mice, rats, and rabbits given the anthracycline anticancer drug doxorubicin.[7-12] Although another study confirmed this protective effect with intraperitoneal administration of doxorubicin in mice, it failed to demonstrate a protective effect when the anthracycline was given intravenously, which is the route of administration in humans.[13] Researchers in one study sounded a cautionary note when they found that coadministration of coenzyme Q₁₀ and radiation therapy decreased the effectiveness of the radiation therapy.[14] In this study, mice inoculated with human small cell lung cancer cells (a xenograft study), and then given coenzyme Q₁₀ and single- dose radiation therapy, showed substantially less inhibition of tumor growth than mice in the control group that were treated with radiation therapy alone. Since radiation leads to the production of free radicals, and since antioxidants protect against free radical damage, the effect in this study might be explained by coenzyme Q₁₀ acting as an antioxidant. As noted previously (General Information ⁵), there is some evidence from laboratory and animal studies that analogs of coenzyme Q₁₀ may have direct anticancer activity.[15,16]

References

1. Bliznakov EG, Adler AD: Nonlinear response of the reticuloendothelial system upon stimulation. Pathol Microbiol (Basel) 38 (6): 393-410, 1972.  [PUBMED Abstract]
   
   
2. Bliznakov EG: Coenzyme Q in experimental infections and neoplasia. In: Folkers K, Yamamura Y, eds.: Biomedical and Clinical Aspects of Coenzyme Q. Vol 1. Amsterdam, The Netherlands: Elsevier/North-Holland Biomedical Press, 1977, pp 73-83. 
   
   
3. Bliznakov EG: Effect of stimulation of the host defense system by coenzyme Q 10 on dibenzpyrene-induced tumors and infection with Friend leukemia virus in mice. Proc Natl Acad Sci U S A 70 (2): 390-4, 1973.  [PUBMED Abstract]
   
   
4. Folkers K, Osterborg A, Nylander M, et al.: Activities of vitamin Q10 in animal models and a serious deficiency in patients with cancer. Biochem Biophys Res Commun 234 (2): 296-9, 1997.  [PUBMED Abstract]
   
   
5. Folkers K, Brown R, Judy WV, et al.: Survival of cancer patients on therapy with coenzyme Q10. Biochem Biophys Res Commun 192 (1): 241-5, 1993.  [PUBMED Abstract]
   
   
6. Ludwig FC, Elashoff RM, Smith JL, et al.: Response of the bone marrow of the vitamin E-deficient rabbit to coenzyme Q and vitamin E. Scand J Haematol 4 (4): 292-300, 1967.  [PUBMED Abstract]
   
   
7. Choe JY, Combs AB, Folkers K: Prevention by coenzyme Q10 of the electrocardiographic changes induced by adriamycin in rats. Res Commun Chem Pathol Pharmacol 23 (1): 199-202, 1979.  [PUBMED Abstract]
   
   
8. Combs AB, Choe JY, Truong DH, et al.: Reduction by coenzyme Q10 of the acute toxicity of adriamycin in mice. Res Commun Chem Pathol Pharmacol 18 (3): 565-8, 1977.  [PUBMED Abstract]
   
   
9. Folkers K, Choe JY, Combs AB: Rescue by coenzyme Q10 from electrocardiographic abnormalities caused by the toxicity of adriamycin in the rat. Proc Natl Acad Sci U S A 75 (10): 5178-80, 1978.  [PUBMED Abstract]
   
   
10. Lubawy WC, Dallam RA, Hurley LH: Protection against anthramycin-induced toxicity in mice by coenzyme Q10. J Natl Cancer Inst 64 (1): 105-9, 1980.  [PUBMED Abstract]
    
    
11. Shinozawa S, Gomita Y, Araki Y: Protective effects of various drugs on adriamycin (doxorubicin)-induced toxicity and microsomal lipid peroxidation in mice and rats. Biol Pharm Bull 16 (11): 1114-7, 1993.  [PUBMED Abstract]
    
    
12. Usui T, Ishikura H, Izumi Y, et al.: Possible prevention from the progression of cardiotoxicity in adriamycin-treated rabbits by coenzyme Q10. Toxicol Lett 12 (1): 75-82, 1982.  [PUBMED Abstract]
    
    
13. Shaeffer J, El-Mahdi AM, Nichols RK: Coenzyme Q10 and adriamycin toxicity in mice. Res Commun Chem Pathol Pharmacol 29 (2): 309-15, 1980.  [PUBMED Abstract]
    
    
14. Lund EL, Quistorff B, Spang-Thomsen M, et al.: Effect of radiation therapy on small-cell lung cancer is reduced by ubiquinone intake. Folia Microbiol (Praha) 43 (5): 505-6, 1998.  [PUBMED Abstract]
    
    
15. Folkers K: The potential of coenzyme Q 10 (NSC-140865) in cancer treatment. Cancer Chemother Rep 2 4 (4): 19-22, 1974.  [PUBMED Abstract]
    
    
16. Folkers K, Porter TH, Bertino JR, et al.: Inhibition of two human tumor cell lines by antimetabolites of coenzyme Q10. Res Commun Chem Pathol Pharmacol 19 (3): 485-90, 1978.  [PUBMED Abstract]
    
    

Human/Clinical Studies

The use of coenzyme Q₁₀ as a treatment for cancer in humans has been investigated in only a limited manner. With the exception of a single randomized trial,[1] which involved 20 patients and tested the ability of coenzyme Q₁₀ to reduce the cardiotoxicity caused by anthracycline drugs, the studies that have been published consist of anecdotal reports, case reports, case series, and uncontrolled clinical studies.[2-7] Reviewed in [8-11]

In view of the promising results from animal studies, coenzyme Q₁₀ was tested as a protective agent against the cardiac toxicity observed in cancer patients treated with the anthracycline drug doxorubicin. It has been postulated that doxorubicin interferes with energy-generating biochemical reactions that involve coenzyme Q₁₀ in heart muscle mitochondria and that this interference can be overcome by coenzyme Q₁₀ supplementation.[3,12,13] Studies with adults and children, including the aforementioned randomized trial, have confirmed the decrease in cardiac toxicity observed in animal studies.[1-4]

The potential of coenzyme Q₁₀ as an adjuvant therapy for cancer has also been explored. In view of observations that blood levels of coenzyme Q₁₀ are frequently reduced in cancer patients,[14,15] Reviewed in [7,9,10] supplementation with this compound has been tested in patients undergoing conventional treatment. An open-label (nonblinded), uncontrolled clinical study in Denmark followed 32 breast cancer patients for 18 months.[5] The disease in these patients had spread to the axillary lymph nodes, and an unreported number had distant metastases. The patients received antioxidant supplementation (vitamin C, vitamin E, and beta carotene), other vitamins and trace minerals, essential fatty acids, and coenzyme Q₁₀ (at a dose of 90 mg /day), in addition to standard therapy (surgery, radiation therapy, and chemotherapy, with or without tamoxifen). The patients were seen every 3 months to monitor disease status (progressive disease or recurrence), and, if there was a suspicion of recurrence, mammography, bone scan, x-ray, or biopsy was performed. The survival rate for the study period was 100% (4 deaths were expected). Six patients were reported to show some evidence of remission; however, incomplete clinical data were provided, and information suggestive of remission was presented for only 3 of the 6 patients. None of the 6 patients had evidence of further metastases. For all 32 patients, decreased use of painkillers, improved quality of life, and an absence of weight loss were reported. Whether painkiller use and quality of life were measured objectively (e.g., from pharmacy records and validated questionnaires, respectively) or subjectively (from patient self-reports) was not specified.

In a follow-up study, 1 of the 6 patients with a reported remission and a new patient were treated for several months with higher doses of coenzyme Q₁₀ (390 and 300 mg/day, respectively).[6] Surgical removal of the primary breast tumor in both patients had been incomplete. After 3 to 4 months of high-level coenzyme Q₁₀ supplementation, both patients appeared to experience complete regression of their residual breast tumors (assessed by clinical examination and mammography). It should be noted that a different patient identifier was used in the follow-up study for the patient who had participated in the original study. Therefore, it is impossible to determine which of the 6 patients with a reported remission took part in the follow-up study. In the follow-up study report, the researchers noted that all 32 patients from the original study remained alive at 24 months of observation, whereas 6 deaths had been expected.[6]

In another report by the same investigators, 3 breast cancer patients were followed for a total of 3 to 5 years on high-dose coenzyme Q₁₀ (390 mg/day).[7] One patient had complete remission of liver metastases (determined by clinical examination and ultrasonography), another had remission of a tumor that had spread to the chest wall (determined by clinical examination and chest x-ray), and the third patient had no microscopic evidence of remaining tumor after a mastectomy (determined by biopsy of the tumor bed).

All 3 of the above-mentioned human studies [5-7] had important design flaws that could have influenced their outcome. Study weaknesses include the absence of a control group (i.e., all patients received coenzyme Q₁₀), possible selection bias in the follow-up investigations, and multiple confounding variables (i.e., the patients received a variety of supplements in addition to coenzyme Q₁₀, and they received standard therapy either during or immediately before supplementation with coenzyme Q₁₀). Thus, it is impossible to determine whether any of the beneficial results was directly related to coenzyme Q₁₀ therapy.

Anecdotal reports of coenzyme Q₁₀ lengthening the survival of patients with pancreatic, lung, rectal, laryngeal, colon, and prostate cancers also exist in the peer-reviewed, scientific literature.[4] The patients described in these reports also received therapies other than coenzyme Q₁₀, including chemotherapy, radiation therapy, and surgery.

Refer to the NCI Web site ⁶ for a list of active clinical trials evaluating the use of coenzyme Q₁₀ in cancer patients.

References

1. Iarussi D, Auricchio U, Agretto A, et al.: Protective effect of coenzyme Q10 on anthracyclines cardiotoxicity: control study in children with acute lymphoblastic leukemia and non-Hodgkin lymphoma. Mol Aspects Med 15 (Suppl): s207-12, 1994.  [PUBMED Abstract]
   
   
2. Folkers K, Wolaniuk A: Research on coenzyme Q10 in clinical medicine and in immunomodulation. Drugs Exp Clin Res 11 (8): 539-45, 1985.  [PUBMED Abstract]
   
   
3. Cortes EP, Gupta M, Chou C, et al.: Adriamycin cardiotoxicity: early detection by systolic time interval and possible prevention by coenzyme Q10. Cancer Treat Rep 62 (6): 887-91, 1978.  [PUBMED Abstract]
   
   
4. Folkers K, Brown R, Judy WV, et al.: Survival of cancer patients on therapy with coenzyme Q10. Biochem Biophys Res Commun 192 (1): 241-5, 1993.  [PUBMED Abstract]
   
   
5. Lockwood K, Moesgaard S, Hanioka T, et al.: Apparent partial remission of breast cancer in 'high risk' patients supplemented with nutritional antioxidants, essential fatty acids and coenzyme Q10. Mol Aspects Med 15 (Suppl): s231-40, 1994.  [PUBMED Abstract]
   
   
6. Lockwood K, Moesgaard S, Folkers K: Partial and complete regression of breast cancer in patients in relation to dosage of coenzyme Q10. Biochem Biophys Res Commun 199 (3): 1504-8, 1994.  [PUBMED Abstract]
   
   
7. Lockwood K, Moesgaard S, Yamamoto T, et al.: Progress on therapy of breast cancer with vitamin Q10 and the regression of metastases. Biochem Biophys Res Commun 212 (1): 172-7, 1995.  [PUBMED Abstract]
   
   
8. Complementary treatments highlighted at recent meeting. Oncology (Huntingt) 13 (2): 166, 1999.  [PUBMED Abstract]
   
   
9. Folkers K: Relevance of the biosynthesis of coenzyme Q10 and of the four bases of DNA as a rationale for the molecular causes of cancer and a therapy. Biochem Biophys Res Commun 224 (2): 358-61, 1996.  [PUBMED Abstract]
   
   
10. Ren S, Lien EJ: Natural products and their derivatives as cancer chemopreventive agents. Prog Drug Res 48: 147-71, 1997.  [PUBMED Abstract]
    
    
11. Hodges S, Hertz N, Lockwood K, et al.: CoQ10: could it have a role in cancer management? Biofactors 9 (2-4): 365-70, 1999.  [PUBMED Abstract]
    
    
12. Usui T, Ishikura H, Izumi Y, et al.: Possible prevention from the progression of cardiotoxicity in adriamycin-treated rabbits by coenzyme Q10. Toxicol Lett 12 (1): 75-82, 1982.  [PUBMED Abstract]
    
    
13. Iwamoto Y, Hansen IL, Porter TH, et al.: Inhibition of coenzyme Q10-enzymes, succinoxidase and NADH-oxidase, by adriamycin and other quinones having antitumor activity. Biochem Biophys Res Commun 58 (3): 633-8, 1974.  [PUBMED Abstract]
    
    
14. Folkers K: The potential of coenzyme Q 10 (NSC-140865) in cancer treatment. Cancer Chemother Rep 2 4 (4): 19-22, 1974.  [PUBMED Abstract]
    
    
15. Folkers K, Osterborg A, Nylander M, et al.: Activities of vitamin Q10 in animal models and a serious deficiency in patients with cancer. Biochem Biophys Res Commun 234 (2): 296-9, 1997.  [PUBMED Abstract]
    
    

Adverse Effects

No serious toxicity associated with the use of coenzyme Q₁₀ has been reported. Reviewed in [1-4] Doses of 100 mg /day or higher have caused mild insomnia in some individuals. Reviewed in [1] Liver enzyme elevation has been detected in patients taking doses of 300 mg/day for extended periods of time, but no liver toxicity has been reported. Reviewed in [1] Researchers in one cardiovascular study reported that coenzyme Q₁₀ caused rashes, nausea, and epigastric (upper abdominal) pain that required withdrawal of a small number of patients from the study.[5] Other reported side effects have included dizziness, photophobia (abnormal visual sensitivity to light), irritability,[5] headache, heartburn, and fatigue.[6]

Certain lipid -lowering drugs, such as the statins (lovastatin, pravastatin, and simvastatin) and gemfibrozil, as well as oral agents that lower blood sugar, such as glyburide and tolazamide, cause a decrease in serum levels of coenzyme Q₁₀ and reduce the effects of coenzyme Q₁₀ supplementation.[7,8] Reviewed in [1,9] Beta-blockers (drugs that slow the heart rate and lower blood pressure) can inhibit coenzyme Q₁₀-dependent enzyme reactions. Reviewed in [1] The contractile force of the heart in patients with high blood pressure can be increased by coenzyme Q₁₀ administration. Reviewed in [1] Coenzyme Q₁₀ can reduce the body’s response to the anticoagulant drug warfarin. Reviewed in [9] Finally, coenzyme Q₁₀ can decrease insulin requirements in individuals with diabetes. Reviewed in [9]

References

1. Pepping J: Coenzyme Q10. Am J Health Syst Pharm 56 (6): 519-21, 1999.  [PUBMED Abstract]
   
   
2. Overvad K, Diamant B, Holm L, et al.: Coenzyme Q10 in health and disease. Eur J Clin Nutr 53 (10): 764-70, 1999.  [PUBMED Abstract]
   
   
3. Hodges S, Hertz N, Lockwood K, et al.: CoQ10: could it have a role in cancer management? Biofactors 9 (2-4): 365-70, 1999.  [PUBMED Abstract]
   
   
4. Heller JH: Disease, the host defense, and Q-10. Perspect Biol Med 16 (2): 181-7, 1973 Winter.  [PUBMED Abstract]
   
   
5. Baggio E, Gandini R, Plancher AC, et al.: Italian multicenter study on the safety and efficacy of coenzyme Q10 as adjunctive therapy in heart failure. CoQ10 Drug Surveillance Investigators. Mol Aspects Med 15 (Suppl): s287-94, 1994.  [PUBMED Abstract]
   
   
6. Feigin A, Kieburtz K, Como P, et al.: Assessment of coenzyme Q10 tolerability in Huntington's disease. Mov Disord 11 (3): 321-3, 1996.  [PUBMED Abstract]
   
   
7. Kaikkonen J, Nyyssönen K, Tuomainen TP, et al.: Determinants of plasma coenzyme Q10 in humans. FEBS Lett 443 (2): 163-6, 1999.  [PUBMED Abstract]
   
   
8. Thibault A, Samid D, Tompkins AC, et al.: Phase I study of lovastatin, an inhibitor of the mevalonate pathway, in patients with cancer. Clin Cancer Res 2 (3): 483-91, 1996.  [PUBMED Abstract]
   
   
9. Coenzyme Q10. In: Jellin JM, Hitchens K, eds.: Natural Medicines Comprehensive Database. Stockton, Calif: Therapeutic Research Faculty, 1999, pp 241-42. 
   
   

Overall Level of Evidence for Coenzyme Q₁₀

To assist readers in evaluating the results of human studies of complementary and alternative medicine (CAM) treatments for cancer, the strength of the evidence (i.e., the “ levels of evidence ”) associated with each type of treatment is provided whenever possible. To qualify for a level of evidence analysis, a study must:

• Be published in a peer-reviewed scientific journal.
• Report on a therapeutic outcome or outcomes, such as tumor response, improvement in survival, or measured improvement in quality of life.
• Describe clinical findings in sufficient detail that a meaningful evaluation can be made.

Separate levels of evidence scores are assigned to qualifying human studies on the basis of statistical strength of the study design and scientific strength of the treatment outcomes (i.e., endpoints) measured. The resulting two scores are then combined to produce an overall score. A table showing the levels of evidence scores for qualifying human studies cited in this summary is presented below. For an explanation of the scores and additional information about levels of evidence analysis of CAM treatments for cancer, refer to Levels of Evidence for Human Studies of Cancer Complementary and Alternative Medicine ².

References

1. Lockwood K, Moesgaard S, Hanioka T, et al.: Apparent partial remission of breast cancer in 'high risk' patients supplemented with nutritional antioxidants, essential fatty acids and coenzyme Q10. Mol Aspects Med 15 (Suppl): s231-40, 1994.  [PUBMED Abstract]
   
   

Changes to This Summary (12/18/2007)

The PDQ cancer information summaries are reviewed regularly and updated as new information becomes available. This section describes the latest changes made to this summary as of the date above.

Purpose of This PDQ Summary ⁸

Added this new section.

More Information

Additional Information about CAM Therapies

• The National Center for Complementary and Alternative Medicine ⁹ (NCCAM).
• The National Cancer Institute Office of Cancer Complementary and Alternative Medicine ¹⁰ (OCCAM).
• CAM on PubMed ¹¹, a special subset of the PubMed scientific literature database created through a partnership between NCCAM and the National Library of Medicine.

About PDQ

• PDQ® - NCI's Comprehensive Cancer Database ¹²

  Full description of the NCI PDQ database.

Other PDQ Summaries

• PDQ® Cancer Information Summaries: Adult Treatment ¹³

  Treatment options for adult cancers.

• PDQ® Cancer Information Summaries: Pediatric Treatment ¹⁴

  Treatment options for childhood cancers.

• PDQ® Cancer Information Summaries: Supportive and Palliative Care ¹⁵

  Side effects of cancer treatment, management of cancer-related complications and pain, and psychosocial concerns.

• PDQ® Cancer Information Summaries: Screening/Detection (Testing for Cancer) ¹⁶

  Tests or procedures that detect specific types of cancer.

• PDQ® Cancer Information Summaries: Prevention ¹⁷

  Risk factors and methods to increase chances of preventing specific types of cancer.

• PDQ® Cancer Information Summaries: Genetics ¹⁸

  Genetics of specific cancers and inherited cancer syndromes, and ethical, legal, and social concerns.

• PDQ® Cancer Information Summaries: Complementary and Alternative Medicine ¹⁹

  Information about complementary and alternative forms of treatment for patients with cancer.

Important:

This information is intended mainly for use by doctors and other health care professionals. If you have questions about this topic, you can ask your doctor, or call the Cancer Information Service at 1-800-4-CANCER (1-800-422-6237).

Glossary Terms

Having to do with the abdomen, which is the part of the body between the chest and the hips that contains the pancreas, stomach, intestines, liver, gallbladder, and other organs.

Treatment given after the primary treatment to increase the chances of a cure. Adjuvant therapy may include chemotherapy, radiation therapy, hormone therapy, or biological therapy.

In biochemistry, reactions that need oxygen to happen or happen when oxygen is present.

A chemical process in which oxygen is used to make energy from carbohydrates (sugars). Also called aerobic respiration, cell respiration, and oxidative metabolism.

A chemical process in which oxygen is used to make energy from carbohydrates (sugars). Also called aerobic metabolism, cell respiration, and oxidative metabolism.

In chemistry, a substance that is similar, but not identical, to another.

An incomplete description of the medical and treatment history of one or more patients. Anecdotal reports may be published in places other than peer-reviewed, scientific journals.

A type of antibiotic that comes from certain types of Streptomyces bacteria. Anthracyclines are used to treat many types of cancer. Anthracyclines damage the DNA in cancer cells, causing them to die. Daunorubicin, doxorubicin, and epirubicin are anthracyclines.

A type of protein made by plasma cells (a type of white blood cell) in response to an antigen (foreign substance). Each antibody can bind to only one specific antigen. The purpose of this binding is to help destroy the antigen. Antibodies can work in several ways, depending on the nature of the antigen. Some antibodies destroy antigens directly. Others make it easier for white blood cells to destroy the antigen.

A drug that helps prevent blood clots from forming. Also called blood thinner.

A drug that is very similar to natural chemicals in a normal biochemical reaction in cells but different enough to interfere with the normal division and functions of cells.

A substance that protects cells from the damage caused by free radicals (unstable molecules made by the process of oxidation during normal metabolism). Free radicals may play a part in cancer, heart disease, stroke, and other diseases of aging. Antioxidants include beta-carotene, lycopene, vitamins A, C, and E, and other natural and manufactured substances.

A lymph node in the armpit region that drains lymph from the breast and nearby areas.

A type of immune cell that makes proteins called antibodies, which bind to microorganisms and other foreign substances, and help fight infections. A B cell is a type of white blood cell. Also called B lymphocyte.

A substance found in yellow and orange fruits and vegetables and in dark green, leafy vegetables. The body can make vitamin A from beta carotene. Beta carotene is being studied in the prevention of some types of cancer. It is a type of antioxidant.

In living cells, chemical reactions that help sustain life and allow cells to grow.

The removal of cells or tissues for examination by a pathologist. The pathologist may study the tissue under a microscope or perform other tests on the cells or tissue. There are many different types of biopsy procedures. The most common types include: (1) incisional biopsy, in which only a sample of tissue is removed; (2) excisional biopsy, in which an entire lump or suspicious area is removed; and (3) needle biopsy, in which a sample of tissue or fluid is removed with a needle. When a wide needle is used, the procedure is called a core biopsy. When a thin needle is used, the procedure is called a fine-needle aspiration biopsy.

A tissue with red blood cells, white blood cells, platelets, and other substances suspended in fluid called plasma. Blood takes oxygen and nutrients to the tissues, and carries away wastes.

The force of circulating blood on the walls of the arteries. Blood pressure is taken using two measurements: systolic (measured when the heart beats, when blood pressure is at its highest) and diastolic (measured between heart beats, when blood pressure is at its lowest). Blood pressure is written with the systolic blood pressure first, followed by the diastolic blood pressure (for example 120/80).

A technique to create images of bones on a computer screen or on film. A small amount of radioactive material is injected into a blood vessel and travels through the bloodstream; it collects in the bones and is detected by a scanner.

Cancer that forms in tissues of the breast, usually the ducts (tubes that carry milk to the nipple) and lobules (glands that make milk). It occurs in both men and women, although male breast cancer is rare.

A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Cancer cells can also spread to other parts of the body through the blood and lymph systems. There are several main types of cancer. Carcinoma is a cancer that begins in the skin or in tissues that line or cover internal organs. Sarcoma is a cancer that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is a cancer that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are cancers that begin in the cells of the immune system. Central nervous system cancers are cancers that begin in the tissues of the brain and spinal cord. Also called malignancy.

Having to do with the heart.

Toxicity that affects the heart.

Having to do with the heart and blood vessels.

A detailed report of the diagnosis, treatment, and follow-up of an individual patient. Case reports also contain some demographic information about the patient (for example, age, gender, ethnic origin).

A group or series of case reports involving patients who were given similar treatment. Reports of case series usually contain detailed information about the individual patients. This includes demographic information (for example, age, gender, ethnic origin) and information on diagnosis, treatment, response to treatment, and follow-up after treatment.

The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.

A chemical process in which oxygen is used to make energy from carbohydrates (sugars). Also called aerobic metabolism, aerobic respiration, and oxidative metabolism.

A drug used to treat cancer.

Treatment with drugs that kill cancer cells.

The muscles, bones, and joints that make up the area of the body between the neck and the abdomen.

An x-ray of the structures inside the chest. An x-ray is a type of high-energy radiation that can go through the body and onto film, making pictures of areas inside the chest, which can be used to diagnose disease.

Having to do with the examination and treatment of patients.

A type of research study that tests how well new medical approaches work in people. These studies test new methods of screening, prevention, diagnosis, or treatment of a disease. Also called clinical trial.

A nutrient that the body needs in small amounts to function and stay healthy. Coenzyme Q10 helps mitochondria (small structures in the cell) make energy. It is an antioxidant that helps prevent cell damage caused by free radicals (highly reactive chemicals). Coenzyme Q10 is fat-soluble (can dissolve in fats and oils) and is found in fatty fish, beef, soybeans, peanuts, and spinach. It is being studied in the prevention and treatment of some types of cancer and heart disease and in the relief of side effects caused by some cancer treatments. Also called CoQ10, Q10, ubiquinone, and vitamin Q10.

The longest part of the large intestine, which is a tube-like organ connected to the small intestine at one end and the anus at the other. The colon removes water and some nutrients and electrolytes from partially digested food. The remaining material, solid waste called stool, moves through the colon to the rectum and leaves the body through the anus.

Forms of treatment that are used in addition to (complementary) or instead of (alternative) standard treatments. These practices generally are not considered standard medical approaches. Standard treatments go through a long and careful research process to prove they are safe and effective, but less is known about most types of CAM. CAM may include dietary supplements, megadose vitamins, herbal preparations, special teas, acupuncture, massage therapy, magnet therapy, spiritual healing, and meditation. Also called CAM.

In a clinical trial, the group that does not receive the new treatment being studied. This group is compared to the group that receives the new treatment, to see if the new treatment works.

A currently accepted and widely used treatment for a certain type of disease, based on the results of past research. Also called conventional therapy.

A type of immune cell that can kill certain cells, including foreign cells, cancer cells, and cells infected with a virus. Cytotoxic T cells can be separated from other blood cells, grown in the laboratory, and then given to a patient to kill cancer cells. A cytotoxic T cell is a type of white blood cell and a type of lymphocyte. Also called cytotoxic T lymphocyte and killer T cell.

In medicine, a shortage of a substance (such as a vitamin or mineral) needed by the body.

The molecules inside cells that carry genetic information and pass it from one generation to the next. Also called DNA.

Any of several diseases in which the kidneys make a large amount of urine. Diabetes usually refers to diabetes mellitus in which there is also a high level of glucose (a type of sugar) in the blood because the body does not make enough insulin or use it the way it should.

A product that is added to the diet. A dietary supplement is taken by mouth, and usually contains one or more dietary ingredient (such as vitamin, mineral, herb, amino acid, and enzyme). Also called nutritional supplement.

The amount of medicine taken, or radiation given, at one time.

A drug that is used to treat many types of cancer and is being studied in the treatment of other types of cancer. Doxorubicin comes from the bacterium Streptomyces peucetius. It damages DNA and may kill cancer cells. It is a type of anthracycline antitumor antibiotic. Also called Adriamycin PFS, Adriamycin RDF, doxorubicin hydrochloride, hydroxydaunorubicin, and Rubex.

Produced inside an organism or cell. The opposite is external (exogenous) production.

In clinical trials, an event or outcome that can be measured objectively to determine whether the intervention being studied is beneficial. The endpoints of a clinical trial are usually included in the study objectives. Some examples of endpoints are survival, improvements in quality of life, relief of symptoms, and disappearance of the tumor.

A protein that speeds up chemical reactions in the body.

Having to do with the upper middle area of the abdomen.

A condition marked by extreme tiredness and inability to function due lack of energy. Fatigue may be acute or chronic.

A major component of fats that is used by the body for energy and tissue development.

An agency in the U.S. federal government whose mission is to protect public health by making sure that food, cosmetics, and nutritional supplements are safe to use and truthfully labeled. The Food and Drug Administration also makes sure that drugs, medical devices, and equipment are safe and effective, and that blood for transfusions and transplant tissue are safe. Also called FDA.

A highly reactive chemical that often contains oxygen and is produced when molecules are split to give products that have unpaired electrons (a process called oxidation). Free radicals can damage important cellular molecules such as DNA or lipids or other parts of the cell.

Cancer that arises in the head or neck region (in the nasal cavity, sinuses, lips, mouth, salivary glands, throat, or larynx [voice box]).

The formation of new blood cells.

A blood pressure of 140/90 or higher. High blood pressure usually has no symptoms. It can harm the arteries and cause an increase in the risk of stroke, heart attack, kidney failure, and blindness. Also called hypertension.

The complex group of organs and cells that defends the body against infections and other diseases.

A protein that acts as an antibody. Immunoglobulins are made by B cells and plasma cells. An immunoglobulin is a type of glycoprotein with two heavy chains and two light chains. Also called Ig.

A substance that increases the ability of the immune system to fight infection and disease.

In the laboratory (outside the body). The opposite of in vivo (in the body).

Invasion and multiplication of germs in the body. Infections can occur in any part of the body and can spread throughout the body. The germs may be bacteria, viruses, yeast, or fungi. They can cause a fever and other problems, depending on where the infection occurs. When the body’s natural defense system is strong, it can often fight the germs and prevent infection. Some cancer treatments can weaken the natural defense system.

A method of putting fluids, including drugs, into the bloodstream. Also called intravenous infusion.

Use of a syringe and needle to push fluids or drugs into the body; often called a "shot."

Difficulty in going to sleep or getting enough sleep.

A hormone made by the islet cells of the pancreas. Insulin controls the amount of sugar in the blood by moving it into the cells, where it can be used by the body for energy.

Within or into muscle. Also called IM.

Within the peritoneal cavity (the area that contains the abdominal organs). Also called IP.

Into or within a vein. Intravenous usually refers to a way of giving a drug or other substance through a needle or tube inserted into a vein. Also called IV.

A researcher in a clinical trial or clinical study.

One of a pair of organs in the abdomen. Kidneys remove waste from the blood (as urine), produce erythropoietin (a substance that stimulates red blood cell production), and play a role in blood pressure regulation.

Research done in a laboratory. These studies may use test tubes or animals to find out if a drug, procedure, or treatment is likely to be useful. Laboratory studies take place before any testing is done in humans.

Having to do with the larynx.

A ranking system used to describe the strength of the results measured in a clinical trial or research study. The design of the study (such as a case report for an individual patient or a randomized double-blinded controlled clinical trial) and the endpoints measured (such as survival or quality of life) affect the strength of the evidence.

Fat.

A large organ located in the upper abdomen. The liver cleanses the blood and aids in digestion by secreting bile.

Cancer that has spread from the original (primary) tumor to the liver.

One of a pair of organs in the chest that supplies the body with oxygen, and removes carbon dioxide from the body.

A type of immune cell that is made in the bone marrow and is found in the blood and in lymph tissue. The two main types of lymphocytes are B lymphocytes and T lymphocytes. B lymphocytes make antibodies, and T lymphocytes help kill tumor cells and help control immune responses. A lymphocyte is a type of white blood cell.

Cancer that begins in cells of the immune system. There are two basic categories of lymphomas. One kind is Hodgkin lymphoma, which is marked by the presence of a type of cell called the Reed-Sternberg cell. The other category is non-Hodgkin lymphomas, which includes a large, diverse group of cancers of immune system cells. Non-Hodgkin lymphomas can be further divided into cancers that have an indolent (slow-growing) course and those that have an aggressive (fast-growing) course. These subtypes behave and respond to treatment differently. Both Hodgkin and non-Hodgkin lymphomas can occur in children and adults, and prognosis and treatment depend on the stage and the type of cancer.

A type of white blood cell that surrounds and kills microorganisms, removes dead cells, and stimulates the action of other immune system cells.

A term for diseases in which abnormal cells divide without control and can invade nearby tissues. Malignant cells can also spread to other parts of the body through the blood and lymph systems. There are several main types of malignancy. Carcinoma is a malignancy that begins in the skin or in tissues that line or cover internal organs. Sarcoma is a malignancy that begins in bone, cartilage, fat, muscle, blood vessels, or other connective or supportive tissue. Leukemia is a malignancy that starts in blood-forming tissue such as the bone marrow, and causes large numbers of abnormal blood cells to be produced and enter the blood. Lymphoma and multiple myeloma are malignancies that begin in the cells of the immune system. Central nervous system cancers are malignancies that begin in the tissues of the brain and spinal cord. Also called cancer.

Cancerous. Malignant tumors can invade and destroy nearby tissue and spread to other parts of the body.

The use of film or a computer to create a picture of the breast.

Surgery to remove the breast (or as much of the breast tissue as possible).

The spread of cancer from one part of the body to another. A tumor formed by cells that have spread is called a “metastatic tumor” or a “metastasis.” The metastatic tumor contains cells that are like those in the original (primary) tumor. The plural form of metastasis is metastases (meh-TAS-tuh-SEEZ).

One millionth of a gram.

Too small to be seen without a microscope.

A measure of weight. A milligram is approximately 450,000 times smaller than a pound and 28,000 times smaller than an ounce.

A measure of volume for a liquid. A milliliter is approximately 950 times smaller than a quart and 30 times smaller than a fluid ounce. A milliliter of liquid and a cubic centimeter (cc) of liquid are the same.

In medicine, a mineral is a nutrient that is needed in small amounts to keep the body healthy. Mineral nutrients include the elements calcium, magnesium, and iron.

Small structures in a cell that are found in the cytoplasm (fluid that surrounds the cell nucleus). Mitochondria make most of the energy for the cell and have their own genetic material that is different from the genetic material found in the nucleus. Many diseases are caused by mutations (changes) in the DNA of mitochondria. Mitochondria are cell organelles.

The smallest particle of a substance that has all of the physical and chemical properties of that substance. Molecules are made up of one or more atoms. If they contain more than one atom, the atoms can be the same (an oxygen molecule has two oxygen atoms) or different (a water molecule has two hydrogen atoms and one oxygen atom). Biological molecules, such as proteins and DNA, can be made up of many thousands of atoms.

Cancer that arises in plasma cells, a type of white blood cell.

The National Cancer Institute, part of the National Institutes of Health of the United States Department of Health and Human Services, is the Federal Government's principal agency for cancer research. The National Cancer Institute conducts, coordinates, and funds cancer research, training, health information dissemination, and other programs with respect to the cause, diagnosis, prevention, and treatment of cancer. Access the National Cancer Institute Web site at http://www.cancer.gov. Also called NCI.

A feeling of sickness or discomfort in the stomach that may come with an urge to vomit. Nausea is a side effect of some types of cancer therapy.

Abnormal and uncontrolled cell growth.

Describes a clinical trial or other experiment in which the researchers know what treatments are being given to each study subject or experimental group. If human subjects are involved, they know what treatments they are receiving.

A clinical study that includes some, but not all, of the eligible patients identified by the researchers during the study registration period. This type of study does not usually have a control group.

Closely monitoring a patient's condition but withholding treatment until symptoms appear or change. Also called active surveillance, expectant management, and watchful waiting.

By or having to do with the mouth.

A chemical process in which oxygen is used to make energy from carbohydrates (sugars). Also called aerobic metabolism, aerobic respiration, and cell respiration.

A condition in which antioxidant levels are lower than normal. Antioxidant levels are usually measured in blood plasma.

A glandular organ located in the abdomen. It makes pancreatic juices, which contain enzymes that aid in digestion, and it produces several hormones, including insulin. The pancreas is surrounded by the stomach, intestines, and other organs.

Having to do with the pancreas.

PDQ is an online database developed and maintained by the National Cancer Institute. Designed to make the most current, credible, and accurate cancer information available to health professionals and the public, PDQ contains peer-reviewed summaries on cancer treatment, screening, prevention, genetics, complementary and alternative medicine, and supportive care; a registry of cancer clinical trials from around the world; and directories of physicians, professionals who provide genetics services, and organizations that provide cancer care. Most of this information, and more specific information about PDQ, can be found on the NCI's Web site at http://www.cancer.gov/cancertopics/pdq. Also called Physician Data Query.

A condition in which the eyes are more sensitive than normal to light.

The clear, yellowish, fluid part of the blood that carries the blood cells. The proteins that form blood clots are in plasma.

The active ingredient in a drug used to lower the amount of cholesterol in the blood and to prevent stroke and heart attack. It is also being studied in the treatment of cancer and other conditions. Pravastatin blocks an enzyme that helps make cholesterol in the body. It may also make tumor cells more sensitive to anticancer drugs. It is a type of HMG-CoA reductase inhibitor, a type of statin, and a type of chemosensitizer.

Research using animals to find out if a drug, procedure, or treatment is likely to be useful. Preclinical studies take place before any testing in humans is done.

In medicine, action taken to decrease the chance of getting a disease or condition. For example, cancer prevention includes avoiding risk factors (such as smoking, obesity, lack of exercise, and radiation exposure) and increasing protective factors (such as getting regular physical activity, staying at a healthy weight, and having a healthy diet).

The original tumor.

The likely outcome or course of a disease; the chance of recovery or recurrence.

Cancer that is growing, spreading, or getting worse.

Multiplying or increasing in number. In biology, cell proliferation occurs by a process known as cell division.

A gland in the male reproductive system. The prostate surrounds the part of the urethra (the tube that empties the bladder) just below the bladder, and produces a fluid that forms part of the semen.

A molecule made up of amino acids that are needed for the body to function properly. Proteins are the basis of body structures such as skin and hair and of substances such as enzymes, cytokines, and antibodies.

Having to do with the simplest organisms in the animal kingdom. Protozoa are single-cell organisms, such as ameba, and are different from bacteria, which are not members of the animal kingdom. Some protozoa can be seen without a microscope.

The overall enjoyment of life. Many clinical trials assess the effects of cancer and its treatment on the quality of life. These studies measure aspects of an individual’s sense of well-being and ability to carry out various activities.

The use of high-energy radiation from x-rays, gamma rays, neutrons, protons, and other sources to kill cancer cells and shrink tumors. Radiation may come from a machine outside the body (external-beam radiation therapy), or it may come from radioactive material placed in the body near cancer cells (internal radiation therapy). Systemic radiation therapy uses a radioactive substance, such as a radiolabeled monoclonal antibody, that travels in the blood to tissues throughout the body. Also called irradiation and radiotherapy.

A study in which the participants are assigned by chance to separate groups that compare different treatments; neither the researchers nor the participants can choose which group. Using chance to assign people to groups means that the groups will be similar and that the treatments they receive can be compared objectively. At the time of the trial, it is not known which treatment is best. It is the patient's choice to be in a randomized trial.

By or having to do with the rectum. The rectum is the last several inches of the large intestine closest to the anus.

Cancer that has recurred (come back), usually after a period of time during which the cancer could not be detected. The cancer may come back to the same place as the original (primary) tumor or to another place in the body. Also called recurrent cancer.

A decrease in the size of a tumor or in the extent of cancer in the body.

A decrease in or disappearance of signs and symptoms of cancer. In partial remission, some, but not all, signs and symptoms of cancer have disappeared. In complete remission, all signs and symptoms of cancer have disappeared, although cancer still may be in the body.

Cancer cells that remain after attempts to remove the cancer have been made.

An error in choosing the individuals or groups to take part in a study. Ideally, the subjects in a study should be very similar to one another and to the larger population from which they are drawn (for example, all individuals with the same disease or condition). If there are important differences, the results of the study may not be valid.

The clear liquid part of the blood that remains after blood cells and clotting proteins have been removed.

A problem that occurs when treatment affects healthy tissues or organs. Some common side effects of cancer treatment are fatigue, pain, nausea, vomiting, decreased blood cell counts, hair loss, and mouth sores.

An aggressive (fast-growing) cancer that forms in tissues of the lung and can spread to other parts of the body. The cancer cells look small and oval-shaped when looked at under a microscope.

In medicine, treatment that experts agree is appropriate, accepted, and widely used. Health care providers are obligated to provide patients with standard therapy. Also called best practice and standard of care.

Any of a group of drugs that lower the amount of cholesterol and certain fats in the blood. Statins inhibit a key enzyme that helps make cholesterol. Statin drugs are being studied in the prevention and treatment of cancer.

Describes a mathematical measure of difference between groups. The difference is said to be statistically significant if it is greater than what might be expected to happen by chance alone. Also called significant.

Beneath the skin.

Adding nutrients to the diet.

A procedure to remove or repair a part of the body or to find out whether disease is present. An operation.

A type of immune cell that can attack foreign cells, cancer cells, and cells infected with a virus. T cells can also help control immune responses. A T cell is a type of white blood cell. Also called T lymphocyte and thymocyte.

A drug used to treat certain types of breast cancer in women and men. It is also used to prevent breast cancer in women who have had ductal carcinoma in situ (abnormal cells in the ducts of the breast) and in women who are at a high risk of developing breast cancer. Tamoxifen is also being studied in the treatment of other types of cancer. It blocks the effects of the hormone estrogen in the breast. Tamoxifen is a type of antiestrogen. Also called tamoxifen citrate.

Having to do with treating disease and helping healing take place.

A group or layer of cells that work together to perform a specific function.

Having to do with poison or something harmful to the body. Toxic substances usually cause unwanted side effects.

A surgical procedure in which tissue or an organ is transferred from one area of a person’s body to another area, or from one person (the donor) to another person (the recipient).

An abnormal mass of tissue that results when cells divide more than they should or do not die when they should. Tumors may be benign (not cancer), or malignant (cancer). Also called neoplasm.

A procedure in which high-energy sound waves are bounced off internal tissues or organs and make echoes. The echo patterns are shown on the screen of an ultrasound machine, forming a picture of body tissues called a sonogram. Also called ultrasound.

A clinical study that lacks a comparison (i.e., a control) group.

Having to do with a virus.

A nutrient that the body needs in small amounts to function and stay healthy. Sources of vitamins are plant and animal food products and dietary supplements. Some vitamins are made in the human body from food products. Vitamins are either fat-soluble (can dissolve in fats and oils) or water-soluble (can dissolve in water). Excess fat-soluble vitamins are stored in the body’s fatty tissue, but excess water-soluble vitamins are removed in the urine. Examples are vitamin A, vitamin C, and vitamin E.

A nutrient that the body needs in small amounts to function and stay healthy. Vitamin E helps prevent cell damage caused by free radicals (highly reactive chemicals). It is fat-soluble (can dissolve in fats and oils) and is found in seeds, nuts, leafy vegetables, and vegetable oils. Not enough vitamin E can result in infertility (the inability to produce children). It is being studied in the prevention and treatment of some types of cancer. Vitamin E is a type of antioxidant.

A drug that prevents blood from clotting. It belongs to the family of drugs called anticoagulants (blood thinners).

A type of high-energy radiation. In low doses, x-rays are used to diagnose diseases by making pictures of the inside of the body. In high doses, x-rays are used to treat cancer.

The cells of one species transplanted to another species.