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Coenzyme Q10 (PDQ®)

Health Professional Version
Last Modified: 01/11/2012

Summary of the 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:

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 1.

Coenzyme Q10 Summary: Reference Numbers and the Corresponding Levels of Evidence
Reference Number  Statistical Strength of Study Design  Strength of Endpoints Measured  Combined Score  
[1]3iii ­ Nonconsecutive case series Diii ­ Indirect surrogates -- tumor response rate3iiiDiii

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]





Glossary Terms

analysis (uh-NA-lih-sis)
A process in which anything complex is separated into simple or less complex parts.
cancer (KAN-ser)
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.
clinical study (KLIH-nih-kul STUH-dee)
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.
complementary and alternative medicine (KOM-pleh-MEN-tuh-ree... all-TER-nuh-tiv MEH-dih-sin)
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.
endpoint (end-point)
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.
levels of evidence (LEH-vulz ... EH-vih-dents)
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.
nonconsecutive case series (non-kun-SEH-kyoo-tiv kays SEER-eez)
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.
outcome (OWT-kum)
A specific result or effect that can be measured. Examples of outcomes include decreased pain, reduced tumor size, and improvement of disease.
peer-reviewed scientific journal (peer-ree-VYOOD SY-en-TIH-fik JER-nul)
A publication that contains original articles that have been written by scientists and evaluated for technical and scientific quality and correctness by other experts in the same field.
quality of life (KWAH-lih-tee ... life)
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.
response (reh-SPONTS)
In medicine, an improvement related to treatment.
therapeutic (THAYR-uh-PYOO-tik)
Having to do with treating disease and helping healing take place.
tumor (TOO-mer)
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.

Table of Links

1http://www.cancer.gov/cancertopics/pdq/levels-evidence-cam/HealthProfessional
2http://www.cancer.gov/cancertopics/pdq/cam/coenzymeQ10/HealthProfessional/Table1