Nutrition in Cancer Care (PDQ®): Supportive care - Health Professional Information [NCI] - Nutrition Implications of Cancer Therapies
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.