Nutrition Implications of Cancer Therapies
The nutritional status of patients diagnosed with cancer entering the treatment process varies. Not everyone begins therapy with anorexia, weight loss, and other symptoms of nutritional problems. For patients who have such symptoms, however, anticancer therapies can complicate the treatment and expected recovery. Many individuals also present with preexisting comorbid diseases and illnesses that further complicate their treatment. Surgery, chemotherapy, and radiation can have a direct (or mechanical) and/or an indirect (or metabolic) negative effect on nutritional status. The success of the anticancer therapy will be influenced by a patient’s ability to tolerate therapy, which will, in turn, be affected by nutritional status preceding treatment. The treating clinician should assess baseline nutritional status (see the Nutrition Screening and Assessment section) and be aware of the possible implications of the various therapies. Patients receiving aggressive cancer therapies typically need aggressive nutrition management.
Surgery is often the primary treatment modality for cancer. Most people with cancer will have some type of surgery. Malnourished surgical patients are at increased risk for postoperative morbidity and mortality. Steps should be taken to attempt to correct nutritional macronutrient and micronutrient deficiencies before surgery if time permits. This involves identification and assessment of the problem, with the possible use of oral liquid nutritional supplements, enteral or parenteral nutritional support, and/or use of pharmacologic therapies to stimulate the appetite (see the Tumor-Induced Effects on Nutritional Status section).
Depending on the procedure, surgery can cause mechanical or physiologic barriers to adequate nutrition, such as a short gut that results in malabsorption after bowel resection. In addition to these mechanical barriers, surgery frequently imposes an immediate metabolic response that increases the energy needs and changes the nutrient requirements necessary for wound healing and recovery at a time when baseline needs and requirements are often not being met.
The following sections highlight various surgical issues for specific cancers. Nutritional complications are usually most notable and severe with cancerous growths and anticancer therapy involving the alimentary canal.
Head and neck cancers
Alcohol abuse is a major risk factor for cancer in the head and neck region and can itself lead to malnutrition. Cancer occurring in this region coupled with curative or palliative surgery can alter a patient’s ability to speak, chew, salivate, swallow, smell, taste, and/or see. Treatment for head and neck cancer can have a profound negative effect on nutritional status.
Nutrition assessment is advised at the initial visit. Clinicians should anticipate additional complicating factors such as the side effects of combined modality therapy (chemotherapy and radiation therapy), as well as the increased nutritional requirements for withstanding these therapies. Because head and neck cancer patients are often malnourished at diagnosis and will undergo therapies that may directly affect their ability to eat, many of these individuals have enteral feeding tubes placed prophylactically before undergoing surgery.
Surgery may take a tremendous toll on the body, but it has reduced mortality and morbidity from gastrointestinal cancers. Anticancer therapy for aerodigestive cancers (e.g., esophageal, gastric, pancreatic, liver, gallbladder, bile duct, and small and large intestine) can result in gastric paresis, alterations in digestion, malabsorption of nutrients, hyperglycemia, elevated lipid levels, hepatic encephalopathy, fluid and electrolyte imbalance, anastomotic and chyle leaks, dumping syndrome, and vitamin and mineral deficiencies. The use of enteral nutritional support is common in the treatment of gastrointestinal cancers. The feeding tube may be placed in the stomach (gastrostomy) or down into the jejunum (jejunostomy).[2,5]
Additional complications and side effects from surgical oncology
Many individuals experience fatigue, pain, and loss of appetite and are unable to consume their regular diet as the result of surgery. Prompt nutritional therapy can help relieve or reduce these problems. Avoiding carbonated or known gas-producing foods will help, as will altering the fiber content in the diet to encourage bowel regularity. A well-balanced diet that contains the recommended amounts of essential nutrients and calories will help promote good wound healing. Finally, proper nutrition and adequate rest may help prevent or treat fatigue.
In 2000, more than 90 different chemotherapy agents were approved for use. These agents are divided into several functional categories. Chemotherapy agents can be used in combination or as single agents, depending on the disease type and health condition of the individual.
Unlike surgery and radiation therapy, cancer chemotherapy is a systemic treatment (not a localized treatment) that affects the whole body (not just a specific part). Consequently, there are potentially more side effects with chemotherapy than with surgery and radiation therapy. The most commonly experienced nutrition-related side effects are anorexia, taste changes, early satiety, nausea, vomiting, mucositis/esophagitis, diarrhea, and constipation (see the Nutritional Suggestions for Symptom Management section). Because side effects of chemotherapy, as well as the cancer itself, can greatly affect nutritional status, healthcare providers need to anticipate possible problems and educate the patient about them  in an effort to prevent malnutrition and weight loss (see the Nutrition Screening and Assessment section). Malnutrition and weight loss can affect a patient’s ability to regain health and acceptable blood counts between chemotherapy cycles; this can directly affect the patient's ability to stay on treatment schedules, which is important in achieving a successful outcome.
Nutritional support or high-calorie/high-protein liquid supplements may be used in an effort to maintain adequate calorie and nutrient intake. Special formulas are available for people with secondary medical conditions such as hyperglycemia or compromised renal function.
Nutritional support during radiation therapy is vital. The effect of radiation therapy on healthy tissue in the treatment field can produce changes in normal physiologic function that may ultimately diminish a patient’s nutritional status by interfering with ingestion, digestion, or absorption of nutrients. Medications such as pilocarpine (Salagen) may be useful in treating the xerostomia (dry mouth) that accompanies radiation therapy. This medicine may reduce the need for artificial saliva agents or other oral comfort agents such as hard candy or sugarless gum.
The side effects of radiation therapy depend on the area irradiated, total dose, fractionation, duration, and volume irradiated. Most side effects are acute, begin around the second or third week of treatment, and diminish 2 or 3 weeks after radiation therapy is completed. Some side effects can be chronic and continue or occur after treatment has been completed.
Individuals receiving radiation therapy to any part of the gastrointestinal tract are more susceptible to nutrition-related side effects. Patients most at risk for developing nutrition-related side effects are those whose cancers involve the aerodigestive tract, including the head and neck, lungs, esophagus, cervix, uterus, colon, rectum, and pancreas. Patients who are receiving radiation therapy to the head and neck region may present to radiation therapy with preexisting malnutrition secondary to an inability to ingest foods because of the disease itself or because of surgery to treat the disease. Many of these patients have a history of high alcohol intake, which also places them at a higher nutritional risk. These individuals are generally at the greatest risk for developing significant nutrition problems and severe weight loss. In a placebo-controlled, double-blind randomized study of 57 patients receiving radiation therapy for head/neck and lung cancer, megestrol acetate (MA) was administered at a dose of 800 mg per day. Patients who received MA demonstrated significant advantages in weight maintenance and some aspects of quality of life.
Nutrition intervention is based on symptom management. Patients who maintain good nutrition are more likely to tolerate the side effects of treatment. Adequate calories and protein can help maintain patient strength and prevent body tissues from further catabolism. Individuals who do not consume adequate calories and protein use stored nutrients as an energy source, which leads to protein wasting and further weight loss.
Some of the more common nutrition-related side effects caused by irradiation to the head and neck include taste alterations or aversions, odynophagia (pain produced by swallowing), xerostomia, thick saliva, mucositis, dysphagia, and stricture of the upper esophagus. Thoracic irradiation may be associated with esophagitis, dysphagia, or esophageal reflux. Diarrhea, nausea, vomiting, enteritis, and malabsorption of nutrients are possible side effects of pelvic or abdominal radiation. (See the Nutritional Suggestions for Symptom Management section.) A prospective, randomized study of patients with colorectal cancer receiving radiation therapy demonstrated that concurrent individualized dietary counseling can improve patients' nutritional intake, status, and quality of life. These improvements, in turn, may reduce radiation-induced morbidity. Patients receiving high-dose radiation or bone marrow transplant should consult with a dietician.
Suggestions for appropriate dietary modifications based on nutrition-related symptoms are widely available for patient and healthcare professional use. For a full listing of dietary suggestions see the Tumor-Induced Effects on Nutritional Status section. A list of appropriate references is also included below.
Many patients who are undergoing radiation therapy will benefit from nutritional supplements between meals. Aggressive nutritional support is indicated when oral intake alone fails to maintain an individual’s weight. Tube feedings are used more frequently than parenteral nutrition, primarily to preserve gastrointestinal function. Tube feedings are usually well tolerated, pose less risk to the patient than parenteral feedings, and are more cost effective. Numerous studies demonstrate the benefit of enteral feedings initiated at the onset of treatment, specifically treatment to head and neck regions, before significant weight loss has occurred.[15-17]
Many nutrition-related side effects result from radiation therapy. Quality of life and nutritional intake can be improved by managing these side effects through appropriate medical nutritional therapy and dietary modifications.
Monoclonal antibodies, which are used to block cancer-cell receptors for growth-stimulating factors, may cause a cascade of symptoms; however, the symptoms most likely to impact nutritional status are fever, nausea, vomiting, and diarrhea. Interferon (a nonspecific immunotherapy) has had the noted nutrition-related side effects of anorexia, nausea, vomiting, and fatigue. Interleukin-2, approved by the U.S. Food and Drug Administration for the single-agent treatment of metastatic renal cell cancer, can also cause symptoms such as fatigue, nausea, vomiting, and diarrhea.[18,19] Response to interleukin-2 treatment varies; some patients gain weight, and some require nutritional support. However, most patients taking interleukin gain weight. Finally, granulocyte-macrophage colony-stimulating factor, a very common therapy used to increase the production of white blood cells, may also cause fever, nausea, vomiting, and diarrhea.
If ignored, these symptoms can cause gradual or drastic weight loss (depending on the severity of the symptoms), which may lead to malnutrition. Malnutrition can complicate the expected healing and recovery process (see the Nutritional Suggestions for Symptom Management section).
Hemopoietic and Peripheral Blood Stem Cell Transplantation
Hemopoietic and stem cell transplant patients have special nutritional requirements. Before their transplant, patients receive high-dose chemotherapy and may also be treated with total-body irradiation (TBI). These treatments, in addition to medications used during transplantation, frequently result in nutritional side effects, which may affect patients' ability to consume an adequate diet. The goal of nutritional support should be the maintenance of nutritional status and protein stores. In addition, transplant patients are at very high risk for neutropenia, an abnormally small number of neutrophils in the blood, that makes them susceptible to multiple infections.[22,23]
To reduce the risk of infections related to stem cell transplantation, most healthcare setting guidelines recommend only cooked and processed foods and restrict raw vegetables and fresh fruits that could cause a food-related infection. Specific dietary restrictions and their duration depend on the type of transplant and the cancer site. In addition to specific dietary restrictions, food safety guidelines should be reviewed and stressed with all transplant patients.
The chemotherapy regimen and complications associated with the transplant may result in numerous problems that adversely affect nutritional intake and status. During the transplant process, patients may experience nutrition-related side effects such as taste changes, oral dryness, thick saliva, mouth and throat sores, nausea and vomiting, diarrhea, constipation, lack of appetite/weight loss, and weight gain. Often during the first few weeks posttransplant, patients are fed intravenously to ensure that they receive sufficient calories, protein, vitamins, minerals, and fluids.
Many patients experience mouth and throat sores 2 to 4 weeks after transplantation. Mucositis is the general term that refers to the erythema, swelling, and ulceration of the intraoral soft-tissue structures and the oral and esophageal mucosa in response to the cytotoxic effect of radiation therapy and high-dose chemotherapy. Mouth and throat sores can make eating and swallowing difficult. TBI may also cause dryness of the mouth, temporarily alter the taste of food, and/or cause thick saliva to form in the mouth and throat. Nausea and vomiting are common problems experienced by transplant patients. Nausea and vomiting may be caused by TBI, chemotherapy, and some medications. TBI, chemotherapy, infection, depression, and fatigue can cause a decrease in appetite and weight loss. Lack of appetite may continue to be a problem long after discharge from the hospital. Patients may also experience gastrointestinal problems such as diarrhea and constipation that could be caused by TBI, chemotherapy, gastrointestinal graft-versus-host disease, infection, and some medications.[26,27]
- American Cancer Society: Understanding Cancer Surgery: A Guide for Patients and Families. Atlanta, Ga: American Cancer Society, 2013. Available online. Last accessed September 3, 2014.
- McGuire M: Nutritional care of surgical oncology patients. Semin Oncol Nurs 16 (2): 128-34, 2000. [PUBMED Abstract]
- Allison G, Dixon D, Eldridge B, et al.: Nutrition implications of surgical oncology. In: McCallum PD, Polisena CG, eds.: The Clinical Guide to Oncology Nutrition. Chicago, Ill: The American Dietetic Association, 2000, pp 79-89.
- Laurell G, Kraepelien T, Mavroidis P, et al.: Stricture of the proximal esophagus in head and neck carcinoma patients after radiotherapy. Cancer 97 (7): 1693-700, 2003. [PUBMED Abstract]
- Persson CR, Johansson BB, Sjöden PO, et al.: A randomized study of nutritional support in patients with colorectal and gastric cancer. Nutr Cancer 42 (1): 48-58, 2002. [PUBMED Abstract]
- Eldridge B: Chemotherapy and nutrition implications. In: McCallum PD, Polisena CG, eds.: The Clinical Guide to Oncology Nutrition. Chicago, Ill: The American Dietetic Association, 2000, pp 61-9.
- Fishman M, Mrozek-Orlowski M, eds.: Cancer Chemotherapy Guidelines and Recommendations for Practice. 2nd ed. Pittsburgh, Pa: Oncology Nursing Press, 1999.
- Donaldson SS: Nutritional consequences of radiotherapy. Cancer Res 37 (7 Pt 2): 2407-13, 1977. [PUBMED Abstract]
- Unsal D, Mentes B, Akmansu M, et al.: Evaluation of nutritional status in cancer patients receiving radiotherapy: a prospective study. Am J Clin Oncol 29 (2): 183-8, 2006. [PUBMED Abstract]
- Chencharick JD, Mossman KL: Nutritional consequences of the radiotherapy of head and neck cancer. Cancer 51 (5): 811-5, 1983. [PUBMED Abstract]
- McQuellon RP, Moose DB, Russell GB, et al.: Supportive use of megestrol acetate (Megace) with head/neck and lung cancer patients receiving radiation therapy. Int J Radiat Oncol Biol Phys 52 (5): 1180-5, 2002. [PUBMED Abstract]
- Polisena CG: Nutrition concerns with the radiation therapy patient. In: McCallum PD, Polisena CG, eds.: The Clinical Guide to Oncology Nutrition. Chicago, Ill: The American Dietetic Association, 2000, pp 70-8.
- Ravasco P, Monteiro-Grillo I, Vidal PM, et al.: Dietary counseling improves patient outcomes: a prospective, randomized, controlled trial in colorectal cancer patients undergoing radiotherapy. J Clin Oncol 23 (7): 1431-8, 2005. [PUBMED Abstract]
- McCarthy D, Weihofen D: The effect of nutritional supplements on food intake in patients undergoing radiotherapy. Oncol Nurs Forum 26 (5): 897-900, 1999. [PUBMED Abstract]
- Tyldesley S, Sheehan F, Munk P, et al.: The use of radiologically placed gastrostomy tubes in head and neck cancer patients receiving radiotherapy. Int J Radiat Oncol Biol Phys 36 (5): 1205-9, 1996. [PUBMED Abstract]
- Heymsfield SB, Greenwood T, Roongpisuthipong C: Dietetics and enteral nutrition: past, present, and future. J Am Diet Assoc 85 (6): 667-8, 1985. [PUBMED Abstract]
- Beer KT, Krause KB, Zuercher T, et al.: Early percutaneous endoscopic gastrostomy insertion maintains nutritional state in patients with aerodigestive tract cancer. Nutr Cancer 52 (1): 29-34, 2005. [PUBMED Abstract]
- American Cancer Society Web Site. Atlanta, Ga: American Cancer Society, 2015. Available online. Last accessed January 8, 2015.
- Samlowski WE, Wiebke G, McMurry M, et al.: Effects of total parental nutrition (TPN) during high-dose interleukin-2 treatment for metastatic cancer. J Immunother 21 (1): 65-74, 1998. [PUBMED Abstract]
- Charuhas PM: Bone marrow transplantation. In: Skipper A, ed.: Dietitian's Handbook of Enteral and Parenteral Nutrition. 2nd ed. Gaithersburg, Md: Aspen Publishers, 1998, pp 273-94.
- Johns A: Overview of bone marrow and stem cell transplantation. J Intraven Nurs 21 (6): 356-60, 1998 Nov-Dec. [PUBMED Abstract]
- Ninin E, Milpied N, Moreau P, et al.: Longitudinal study of bacterial, viral, and fungal infections in adult recipients of bone marrow transplants. Clin Infect Dis 33 (1): 41-7, 2001. [PUBMED Abstract]
- Jantunen E, Ruutu P, Piilonen A, et al.: Treatment and outcome of invasive Aspergillus infections in allogeneic BMT recipients. Bone Marrow Transplant 26 (7): 759-62, 2000. [PUBMED Abstract]
- Roberts SR: Bone marrow and peripheral blood stem cell transplantation. In: Lysen LK, ed.: Quick Reference to Clinical Dietetics. Gaithersburg, Md: Aspen Publishers, Inc, 1997, pp 162-8.
- Weisdorf SA, Schwarzenberg SJ: Nutritional support of bone marrow transplantation recipients. In: Forman SJ, Blume KG, Thomas ED, eds.: Bone Marrow Transplantation. Boston, Mass: Blackwell Scientific Publications, 1994, pp 327-36.
- Charuhas PM: Medical nutrition therapy in bone marrow transplantation. In: McCallum PD, Polisena CG, eds.: The Clinical Guide to Oncology Nutrition. Chicago, Ill: The American Dietetic Association, 2000, pp 90-8.
- Shapiro TW, Davison DB, Rust DM, eds.: A Clinical Guide to Stem Cell and Bone Marrow Transplantation. Boston, Mass: Jones and Bartlett Publishers, 1997.