Weight loss is a reduction in body mass characterized by a loss of adipose tissue (body fat) and skeletal muscle.
Description
Unintentional weight loss is the most common symptom of cancer and often a side effect of cancer treatments. A poor response to cancer treatments, reduced quality of life, and shorter survival time may result from substantial weight loss. The body may become weaker and less able to tolerate cancer therapies. As body weight decreases, body functionality declines and may lead to malnutrition, illness, infection, and perhaps death.
Severe malnutrition is typically defined in two ways: functionally (increased risk of morbidity and/or mortality) and by degree of weight loss (greater than 2% per week, 5% per month, 7.5% per 3 months, and 10% per 6 months). Without considering a specific time course, grading is as follows:
Grade 0 = less than 5.0% weight loss
Grade 1 = 5.0% to 9.9%
Grade 2 = 10.0% to 19.9%
Grade 3 = greater than 20.0%
Grade 4 (life-threatening) is not specifically defined. Paying attention to weight loss at an early stage is necessary to prevent deterioration of weight, body composition, and performance status.
Causes
There are many reasons for weight loss in cancer patients, including appetite loss because of the effect of cancer treatments (chemotherapy, radiation therapy, or biological therapy) or due to psychological factors such as depression. Patients may suffer from anorexia and lose desire to eat, and thus consume less energy. When inadequate calories are consumed, it can lead to "wasting" of body stores (muscle and adipose tissue). Weight loss may be temporary or may continue at a life-threatening pace.
Weight loss may be also be a consequence of an increased requirement for calories (energy) due to infection, fever, or the effects of the tumor or cancer treatments. If infection or fever is present, it is necessary to consider that there is an increased caloric need of approximately 10% to 13% per degree above 98.6°F (37°C). Therefore, energy intake has to be increased to account for this rise in body temperature.
Weight loss may be a result of a common problem in cancer called cachexia. Approximately half of all cancer patients experience cachexia, a wasting syndrome that induces metabolic changes leading to a loss of muscle and fat. It has been proposed that cachexia may be due to the effects of the tumor, but this is debatable considering some patients with very large tumors do not experience cachexia, while others do even though tumors are less than 0.01% of body mass. Cachexia is most common in patients with pancreatic and gastric cancer. Approximately 83% to 87% of these patients experience weight loss. Cachexia is characterized by symptoms such as a decreased appetite, fatigue, and poor performance status. It can occur in individuals who consume enough food, but due to disease complications, cannot absorb enough nutrients (i.e. fat malabsorption). Although energy expenditure is sometimes increased, cachexia can occur even with normal energy expenditure. Cachexia is multifactorial in nature and associated with mechanical factors, psychological factors, changes in taste, and cytokines. It should be distinguished from anorexia, where there is a loss of desire to eat, resulting in weight loss. Cachexia is serious in cancer patients, sometimes leading to death.
Special concerns
In order to allow normal tissue repair following aggressive cancer therapies, patients require adequate calories and macronutrients in the form of protein, carbohydrates, and fat. Inadequate consumption of food and/or poor nutrition may impair the ability of a patient to tolerate a specific therapy. If a low tolerance to therapy necessitates a decrease in dose, the therapy's effectiveness could be compromised. Wound healing may also be impaired with poor nutrition and inadequate energy intake.
Research has demonstrated that men often experience significantly more weight loss than women over the
course of the disease and lose weight much faster. On average, survival time for men is shorter than for women. Significant predictors of patient survival are stage of disease, initial weight-loss rate, and gender.
Treatments
Nutritional problems related to side effects should be addressed to ensure adequate nutrition and prevent weight loss. In particular, cancer patients should maintain an adequate intake of calories and protein to prevent protein-calorie malnutrition. The patient's caloric requirements can be calculated by a dietitian or doctor since nutrient requirements vary considerably from patient to patient.
The following dietary tips may help to reduce weight loss:
Eat more when feeling the hungriest.
Eat foods that are enjoyed the most.
Eat several small meals and snacks instead of three large meals. A regular meal schedule should be kept so meals are not missed.
Have ready-to-eat snacks on hand such as cheese and crackers, granola bars, muffins, nuts and seeds, canned puddings, ice cream, yogurt, and hard boiled eggs.
Eat high-calorie foods and high-protein foods.
Take a small meal as to enjoy the satisfaction of finishing a meal. Have seconds if still hungry.
Eat in a pleasant atmosphere with family and friends if desired.
Make sure to consume at least eight to ten glasses of water per day to maintain fluid balance.
Consider commercial liquid meal replacements such as Ensure, Boost, Carnation, and Sustacal.
An appetite stimulant may be given in order to prevent further weight loss such as megestrol acetate or dexamethasone. In clinical trials, both these medications appear to have similar and effective appetite stimulating effects with megestrol acetate having a slightly better toxicity profile. Fluoxymesterone has shown inferior efficacy and an unfavorable toxicity profile.
Alternative and complementary therapies
Depression may affect approximately 15% to 25% of cancer patients, particularly if the prognosis for recovery is poor. If anorexia is due to depression, there are antidepressant choices available through a physician. Counseling may be also be sought through a psychologist or psychiatrist to cope with depression.
It is important to check with a dietitian or doctor before taking nutritional supplements or alternative therapies because they may interfere with cancer medications
or treatments. St. John's Wort has been used as a herbal remedy for treatment of depression, but it and prescription antidepressants is a dangerous combination that may cause symptoms such as nausea, weakness, and may cause one to become incoherent.
Keane, Maureen, et al. What to Eat If You Have Cancer: A Guide to Adding Nutritional Therapy to Your TreatmentPlan. Lincolnwood, IL: National Textbook Company/Contemporary Publishing Group, 1996.
Nixon, Daniel W., M.D., Jane A. Zanca, and Vincent T. DeVitaThe Cancer Recovery Eating Plan: The Right Foods to Help Fuel Your Recovery. New York: Times Books, 1996.
Quillin, Patrick, and Noreen Quillin. Beating Cancer With Nutrition—Revised. Sun Lakes, AZ: Bookworld Services, 2001.
PERIODICALS
Kant, Ashima, et al. "A Prospective Study of Diet Quality and Mortality in Women." JAMA 283, no. 16 (2000): 2109-15.
Loprinzi, C.L., et al. "Randomized Comparison of Megestrol Acetate Versus Dexamethasone Versus Fluoxymesteronefor the Treatment of Cancer Anorexia/Cachexia." Journal of Clinical Oncology 7, no. 10 (1999): 3299-306.
Roubenoff, Ronenn. "The Pathophysiology of Wasting in the Elderly." The Journal of Nutrition 129, no. 1 (1999):256-9.
Tisdale, Michael J. "Wasting in cancer." The Journal of Nutri tion 129, no. 1 (1999): 243-6.
ORGANIZATIONS
National Center for Complementary and Alternative Medicine (NCCAM). 31 Center Dr., Room #5B-58, Bethesda, MD20892-2182. (800) NIH-NCAM, Fax (301) 495-4957.<http://nccam.nih.gov>.
American Institute for Cancer Research. 1759 R Street NW, Washington, D.C. 20009. (800) 843-8114 or (202) 328-7744. <http://www.aicr.org>, e-mail: support@aicr.org.
Crystal Heather Kaczkowski, MSc.
Anorexia
—A condition frequently observed in cancer patients characterized by a loss of appetite or desire to eat.
Cachexia
—A condition where the bodyweight "wastes" away, characterized by a constant loss of weight, muscle, and fat.
Cancer
—A term for diseases in which abnormal cells divide without control. Cancer cells can invade nearby tissues and can spread through the bloodstream and lymphatic system to other parts of the body.
Chemotherapy
—Chemotherapy kills cancer cells using drugs taken orally or by needle in a vein or muscle. It is referred to as a systemic treatment due to fact that it travels through the bloodstream and kills cancer cells outside the small intestine.
Enteral nutrition
—Feedings administered through a nose tube (or surgically placed tubes) for patients with eating difficulties.
Parenteral nutrition
—Feeding administered most often by an infusion into a vein. It can be used if the gut is not functioning properly or due to other reasons that prevent normal or enteral feeding.
Protein-calorie malnutrition
—A lack of protein and calories are consumed to sustain the body composition, resulting in weight loss and muscle wasting.
Radiation therapy
—Also called radiotherapy; uses high-energy rays to kill cancer cells.
Wasting
—When inadequate calories are consumed, it can lead to "wasting" or depletion of body mass. Wasting results in weight loss in tissues such as skeletal muscle and adipose tissue (fat).
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