Get this document via a secure connection
The NCI will no longer support CancerMail after November 2002. If you have comments about the NCI's cancer information delivery services, contact us by e-mail at cancer.govstaff@mail.nih.gov or call 301-496-9096.
###########################################################################
Anorexia, the loss of appetite or desire to eat, is the most common symptom in people with cancer that may occur early in the disease process or later as the tumor grows and metastasizes.[1] Anorexia is present in 15% to 25% of all cancer patients at the time of diagnosis and is almost universal in patients with widely metastatic disease.[2,3] Anorexia is the most common cause of decreased nutrient intake triggering malnutrition and progressive inanition (progressive deterioration with muscle wasting and body compositional change) in malignancy.
Cachexia is a clinical wasting syndrome evidenced by weakness and a marked and progressive loss of body weight, fat, and muscle.[4] Anorexia and cachexia frequently occur together, but cachexia may occur in individuals who are ingesting adequate calories and protein but experience malabsorption of nutrients. It has been estimated that one half of all people with cancer experience cachexia, two thirds while in a terminal phase of the disease.[5] In addition, investigators have found no association between cachexia and tumor size, type, or extent.[6] It has been observed that cancer cachexia differs from simple starvation.[7] Individuals adapt to starvation by decreasing their basal metabolic rate, whereas in cancer patients, the basal metabolic rate is not adaptive and may be increased, decreased, or normal.[8] Although the exact mechanisms causing cancer cachexia are unknown, several theories regarding its pathogenesis point to a complex mix of tumor, host, and treatment variables, which make this syndrome difficult to study.
The prognostic impact of weight loss and malnutrition has been documented since the 1930s [9] in benign disease and later in malignant disease.[10-13] It has been estimated that up to 20% of people with cancer may die of the effects of cancer-included or treatment-related inanition. Additionally, the impact of malnutrition on health care costs is substantial.[14,15]
In addition to local tumor effects (from either the tumor itself or the patient's response to the tumor), nutritional problems can also stem from metabolic alterations.[2] Marked alteration in normal metabolism of carbohydrate, protein, and lipid can occur. Tumor cells may derive significant energy from metabolism of glucose to lactate (Cori cycle) rather than from more complete oxidation of carbon dioxide and water (Krebs cycle).[3] Additionally, conversion of lactate to glucose for gluconeogenesis by the liver consumes six ATP molecules per lactate-glucose cycle, producing energy-inefficient cycling. Tumor cells have an increased requirement for glucose as an energy source, either through altered enzymatic activity or due to relative hypoxia induced by poor tumor vascularization. Differences in the contribution of Cori cycle activity have been seen in patients who lose weight and in those with stable weight.[2] Inhibition of phosphoenolpyruvate carboxykinase by hydrazine sulfate may decrease excess Cori cycle activity and improve glucose tolerance in cancer patients, but weight loss may not be reversed.[2] Altered protein metabolism in patients with cancer may stem from increased uptake of amino acids by the tumor cells compared with that of normal cells, decreased protein synthesis, increased protein degradation, and protein loss through fistulas or by gastrointestinal losses. In addition, decreased intake secondary to anorexia, when need is increased or normal, is often the basis of negative nitrogen balance. Altered lipid metabolism can occur as a result of mobilization and the use of fatty acids as an additional energy source when the glucose supply of the body is exhausted by the tumor.[4] A decrease in fat mobilization has also been observed.[5,6]
Mediators of primary cachexia (i.e., cachexia without a mechanical or function etiology) can include substances with hormone-like characteristics or products of host tissues that influence metabolism indirectly. The latter include a number of cytokines such as tumor necrosis factor (TNF-alpha), interleukin-6, and gamma-interferon. Additionally, lipid mobilizing factors have also been implicated.[2] Lack of enteral stimulation may increase levels of circulating cytokines.
In addition to alterations in carbohydrate, protein, and lipid metabolism, cancer cells produce peptides, oligonucleotides, and other metabolites that may be responsible for the genesis of anorexia and cachexia.[2] For example, tumor-produced substances may alter a person's sense of taste, leading to an aversion to meat and a decreased taste sensation. Tumors may cause anorexia through a peripheral effect on neuroendocrine cells or neuroreceptors and through a direct effect on hypothalamic and other central nervous system peptidergic and responder cells. Early satiety or a sense of fullness is a frequent symptom in anorectic cancer patients, suggesting the importance of inhibitory signals from the gastrointestinal tract in limiting their food intake. Tumors can also produce hormone substances, similar to those seen in paraneoplastic syndromes, which can alter nutrient intake, absorption, and metabolism.[7]
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).[3] In the cooperative group format, nutrition toxicity does not generally take into account baseline deficit and includes degrees of weight loss that are much greater than the above criteria. Grading (without consideration of time course) is as follows: grade 0 = less than 5.0% loss, grade 1 = 5.0%-9.9%, grade 2 = 10.0%-19.9%, grade 3 = greater than 20.0%. Grade 4 (life-threatening) is not specifically defined. Attention to weight loss at an earlier time point is required to successfully prevent deterioration of weight, body composition, and performance status.
Factors such as living alone, inability to cook or prepare meals, or even to walk to the kitchen as a result of physical limitations can contribute to eating disorders. A thorough evaluation of the home situation by a social worker or visiting nurse may identify easily correctable factors that contribute to poor eating habits.
Establishing the cancer diagnosis and initiating treatment often require the patient to spend large amounts of time away from normal routines, including meals. Cultural food preferences may not be accessible in treatment settings or may not be well tolerated because of treatment side effects. A person who enjoys hot, spicy food and has esophagitis may dislike the taste of bland food and eat very little. Taste alterations can psychologically affect a person's appetite and desire for food.
Unfortunately, lack of adequate nutritional intake leads to progressive nutritional deterioration, representing to the patient and family, progression of the cancer process. The wasting is a constant reminder to the patient, family, and health care team of the cancer diagnosis and expected poor prognosis. This can significantly influence quality of life, social interaction, and outlook. Additionally, with progressive wasting, and its associated fatigue, the person generally decreases social interaction. Because of the role food and eating have in society, this can serve as a significant isolation factor for a person with cancer.
Studies have reported a positive impact of exercise (e.g., walking or mild aerobic) on the sense of well-being, nausea and vomiting, and nutritional intake.[2] Patients forced to rely on artificial feeding methods (including forced oral feeding as well as enteral or parenteral feeding) can experience depression, body image changes, and stress related to problems with feeding tubes and equipment.[3] Problems related to nutrition have been identified by cancer patients as the most important factor in affecting their sense of well-being, more important than sexuality and continued employment.[4]
Obtaining a quantitative as well as qualitative dietary history can be helpful in dietary assessment, especially as a means of demonstrating to the person with cancer and his or her family or caregiver, that changes can be made to increase calorie, protein, and micronutrient intake. Useful data also include specific likes, dislikes, and intolerances of the person with cancer. The latter may help to determine the need for specific supplemental enzymes (lactase, other disaccharidases, or pancreatic enzymes).
Anthropometric measurements such as skin fold thickness and midarm muscle circumference are not useful in clinical situations. However, clinical palpation of the tricep muscle can often provide an excellent estimate of nutrition, since extensors tend to lose muscle faster than flexors.[4] This method of nutritional assessment is limited by both the technique and interobserver variability. Laboratory evaluations that may contribute to nutritional evaluation or appropriate nutritional intervention include assessment of visceral protein status (serum transferrin or albumin), renal and liver function, pancreatic endocrine function (glucose), serum electrolytes and minerals (calcium, magnesium, and phosphorus), and hematologic evaluation (total lymphocyte count and red cell indices). Although not routinely used, delayed cutaneous hypersensitivity testing (skin test antigens) may be helpful to gauge systemic immune function.
Determination of nitrogen balance by 24-hour urinary urea nitrogen (UUN) is helpful in nutritional intervention regimens, particularly in the use of enteral or parenteral nutrition. The aim of nutritional intervention is to minimize the degree of negative nitrogen balance (i.e., excessive loss of body protein not compensated by adequate nutritional intake). Nitrogen balance is defined as nitrogen intake (in grams) minus nitrogen output (in grams) and can be estimated from (protein intake/6.25) - (UUN+4). If nitrogen intake is less than output, the patient is considered to be in negative nitrogen balance, with a net loss of body protein. This contributes to progressive muscle wasting, fatigue, and immune compromise.
1. Presence of a functional gastrointestinal tract
2. Type of therapy (independent of palliative or curative intent), i.e., site
and extent of surgical resection, specific type of chemotherapy, site and size
of radiation field, use of biologic response modifiers, or multimodality
therapy
3. Quality of life, performance status, or prognosis
4. Cost effectiveness and cost-utility determinations
It is believed that maintenance of body composition and adequate nutritional status can help people with cancer feel and look better and can maintain or improve performance status and daily functional status. It may also help them tolerate therapy.[1] The type of nutritional intervention used will depend on the basis of the nutritional risk or deficit. Problems caused by local tumor effects may subside when the tumor responds to therapy. Those nutritional impact symptoms related to side effects of therapy must be proactively addressed to ensure adequate symptom control measures. (Refer to the PDQ summaries on Constipation, Impaction, and Bowel Obstruction; Pain; Nausea and Vomiting; and Oral Complications for more information.)
A major cause of anorexia in patients with cancer is food odor. Patients suffering from anorexia should not be in a room where the odors of food preparation can be detected. Foods with reduced odors are preferable for patients with cancer. This explains why cancer patients will often eat best at breakfast, since many breakfast foods have little odor.
Suggestions for helping people with cancer manage anorexia include the following:[2-4]
1. Eat small frequent meals (every 1-2 hours by the clock).
2. Eat food (including snacks) that is caloric- and protein-dense.
3. Avoid foods low in calories and protein and avoid empty calories (i.e.,
food without protein and micronutrients, such as soda).
4. Avoid liquids with meals (unless used sparingly to improve dry mouth or
dysphagia) to decrease problem of early satiety.
5. Time meals to coincide with periods during the day when the patient is
feeling best; use nutritional supplements at times of decreased appetite or
desire to eat. (Generally, patients tend to feel better and have improved
appetites early in the day with a progressive decrease in appetite as the day
progresses.)
6. Taste-test several different commercially available nutritional supplements
or different high-calorie, high-protein drink or pudding recipes. Adding the
juice from half of a freshly-squeezed lemon can help lessen the excessive
sweetness and bitter aftertaste that sometimes distresses patients with cancer,
but which may not be detectable to individuals who do not have cancer.
7. Stimulate appetite with light exercise (e.g., walking), glass of wine or
beer if not contraindicated, and use of orexigenic agents (appetite
stimulants).
8. Add extra calories and protein to food (e.g., butter, skim milk powder,
honey, brown sugar).
9. Take medications with high-calorie fluids (e.g., commercial nutritional
supplement) unless the medication must be taken on an empty stomach.
10. Make surroundings pleasant and varied; food presentation should be
attractive (e.g., try new recipes, eat with friends, prepare food with color
and texture variation).
11. Experiment with recipes, flavorings, spices, types and consistencies of
food. This is important since food preferences may change from day to day.
12. Avoid strong aromas if they are bothersome. Strategies include the use of
boiling bags, cooking outdoors on a grill, the use of kitchen fan when cooking,
serving cold plates rather than hot foods (since odors come from the rising
steam), and removal of hospital food tray covers in the hallway rather than at
the patient's bedside to dissipate some of the odors. A portable fan can be
used to blow away the aroma of hot foods. Food ordered from outside so that
preparation odors are not detected will often be tolerated if consumed
immediately after arrival (e.g. pizza).
Suggestions for helping people with cancer manage taste changes include the following:
1. Use plastic utensils if patient experiences metallic taste while eating.
2. Substitute poultry, fish, eggs, and cheese for red meat.
3. Marinate meats with sweet marinades or sauces.
4. Serve meats chilled rather than hot.
5. Use extra seasonings, spices, and flavorings, but avoid flavorings that
are very sweet or very bitter. An elevated threshold for taste may make food
taste bland or boring.
6. Substitute milk shakes, puddings, ice cream, cheese, and other high-protein
foods for meats if patient experiences an aversion to meat.
7. Rinse mouth before eating.
8. Use lemon-flavored drinks to stimulate saliva and taste, but avoid
artificial lemon and use sweeteners sparingly.
Suggestions for prevention of conditioned taste aversions include the following:
1. Try new foods and supplements when feeling best/well, e.g., on Sundays for
patients undergoing daily radiation therapy or after the patient leaves the
hospital rather than during chemotherapy infusion.
2. Eat lightly on the morning of or several hours prior to receiving
chemotherapy.
3. Separate novel taste introductions from noxious stimuli.
Suggestions for lessening or alleviating either dry mouth or dysphagia include the following:
1. Eat soft or moist foods.
2. Process foods in blender.
3. Lubricate foods with creams, gravies, or oils.
4. Avoid rough, irritating foods.
5. Avoid hot or cold foods.
6. Avoid foods that adhere to the roof of the mouth.[5]
7. Take small bites and chew thoroughly.[5]
Suggestions for stomatitis: (Refer to the PDQ summary on Oral Complications for more information.)
No matter what the nutritional deficit, the person with cancer should be encouraged to maintain a positive attitude toward treating the cause and assuring adequate intake of protein and calories. Calculating individualized calorie and protein requirements and explaining to the person with cancer (and/or family or caregiver) will allow specific and realistic goals. The actual amount of protein and calories needed by each cancer patient will vary depending on the person's baseline and current nutritional status, particular nutritional deficits, and individual factors.
The protein requirement for non-weight losing individuals is approximately 0.5 grams per pound of ideal body weight. For the person who has lost weight, is febrile, or is on medications that increase protein requirements, such as corticosteroids, it is important to aim for approximately 0.7 grams per pound. Ideal body weight (IBW) is calculated as follows:
------------------------------------------------------------------------------
General guidelines of calories required (assuming light activity):
Underweight adults - multiply weight in pounds by 18
Normal weight adults - multiply weight in pounds by 16
Overweight adults - multiply weight in pounds by 13
------------------------------------------------------------------------------
Additional calories and increased protein intake may be required for specific people and situations. An oncology nutritionist (dietitian, diet technician, nurse, or physician with specialized education or training in nutrition) can offer guidance in determining the appropriate macronutrient (calories and protein) and micronutrient (vitamins, electrolytes, minerals) needs and options for nutritional intervention.
General indications for enteral nutrition (gastric and duodenal/jejunal, with site dependent on the intake gastrointestinal impediment) include the following:
1. Upper gastrointestinal impediment to adequate oral intake (dysphagia,
esophageal stricture, tumor, gastroparesis, gastric outlet obstruction, etc.).
2. Combined modality therapy with chemotherapy and radiation therapy
(especially with radiation therapy to the upper aerodigestive tract) with
known esophageal or gastrointestinal tract toxicity that will limit
adequate oral intake.
3. Anorexia and/or psychologic inability (e.g., severe depression,
confusion/disorientation) to maintain adequate oral intake.
4. Contraindications/inability to take large volumes of oral nutrition,(e.g.,
pain with bolus eating).
General contraindications to enteral nutrition include the following:
1. Bowel obstruction.
2. Intractable nausea and vomiting unresponsive to optimal antiemetic regimen
(Refer to the PDQ summary on Nausea and Vomiting for more information.)
3. Severe short gut with intractable gastrointestinal output despite attempts
with appropriate enteral formulations and pharmacologic intervention (e.g.,
somatostatin).
4. Upper gastrointestinal tract or high-output fistula (tumor-related or
iatrogenic).
General indications for parenteral nutrition (complete or supplemental) include the following:
1. Nonfunctioning gastrointestinal tract in the following contexts:
a. Temporary problems impeding oral or enteral intake for longer than 10
days, especially with baseline nutritional deficit.
b. Obstruction or other mechanical problems expected to respond to
antineoplastic therapy or surgical intervention.
c. Multiple and/or noncorrectable obstructive/mechanical problems
associated with an indolent cancer.
2. Severe short gut secondary to surgical resection, radiation enteritis,
high gastrointestinal fistula and inability to maintain weight and body
composition with appropriate enteral regimen.
3. Severe and/or continuing nutritional deterioration in a person with
indolent cancer or any malignancy in which malnutrition, rather than
cancer is the primary problem.
General contraindications to parenteral nutrition include the following:
1. Functional gut.
2. Limited life expectancy (< 40 days).
3. Lack of adequate vascular access.
4. Lack of severe nutritional deficit such as temporary inability to eat
(e.g., post surgery).
Although there remains continued controversy concerning the ultimate benefit of nutritional support,[2] it is believed that a properly nourished cancer patient is better able to tolerate both the cancer therapy and its complications.[3,4] The delivery method chosen for nutritional support should be based on the individual's physiologic requirements, degree of nutritional debilitation, disease process, estimated duration for the need of support, and the resources available. If the gastrointestinal tract is functioning and not adversely affected by the cancer treatment, enteral support is the route of choice, especially when dealing with issues of system immune function. Options for placement of enteral feeding tubes include non-surgical (via nasal route) as well as endoscopic, radiologic, laparoscopic, and open surgical placement. Practical issues of tube options and formulations have been reviewed.[5,6]
Nutritional support: pharmacological approaches [7]
Pharmacologic intervention to increase oral nutritional intake can range from pain management to treatment of constipation or diarrhea, the use of gastric prokinetic agents, and the use of specific orexigenic agents (appetite stimulants).[8] Megestrol acetate (at a recommended dose of 800 mg/day) has shown success.[9,10] Corticosteroid use in situations other than terminal care is generally not indicated because of exacerbation of progressive muscle wasting. Dronabinol as an appetite stimulant has been used primarily in AIDS cachexia, but has been suggested for cancer patients, with a dose of 2.5 mg/day to 5 mg/day.
Hydrazine sulfate has been studied in three multicenter, randomized, phase III trials sponsored by the National Cancer Institute, however no clinical benefits were found. These trials included 600 patients diagnosed with advanced lung cancer and advanced colon cancer.[11-13] The end points in these studies included survival, weight gain, nutritional parameters and quality of life. The results of these three studies were negative, with no benefit seen. In the two studies of advanced lung cancer patients, the addition of hydrazine sulfate to a standard chemotherapy regimen resulted in somewhat worse quality of life, with no effect on weight gain or loss and a suggestion of decreased time to disease progression and survival when compared with placebo.[11,12] In the trial evaluating hydrazine sulfate in metastatic colon cancer, the survival time for patients receiving the hydrazine was decreased compared with patients receiving placebo.[13] Compared with patients receiving placebo, patients receiving hydrazine sulfate demonstrated a more rapid deterioration of performance scores and quality of life indices, and also experienced more rapid weight loss. The incidence of severe and life threatening treatment-related adverse effects, particularly sensory and motor neuropathies were significantly greater among patients who received hydrazine sulfate.
|
Browse and Submit Oncology Conferences |
|
Sponsors:
|
small video clip about our work (200 Kbit/s)
|
| Back to the Cancernet
contents overview Questions? Mail them to us! |
We subscribe to the HONcode
principlesof the Health On the Net Foundation
|