For several decades, the nutritional deterioration of patients diagnosed with cancer has been recognized, and attempts have been made to prevent or reverse it. However, with all the advancements in technology and medicine, it is somewhat surprising to find that little has altered in the approach or the management of cancer patients suffering from a compromised nutritional status or altered metabolism due to either the treatment or the disease process.
Inadequate Food Intake
We are all too familiar with the problems experienced by many cancer patients-anorexia, metabolic abnormalities, and changes in energy expenditure- but most importantly impaired and inadequate food intake. As a result, we still see serious clinical effects of malnutrition such as decubiti, impaired wound healing, electrolyte and fluid imbalances, weakness, fatigue, and impaired immune responses. The gastrointestinal tract is a site easily compromised by treatment modalities as well as tumor growth. Yet the gut represents 70% to 80% of immunologic-secreting cells. Almost 50% of the mass of the immune system lines the gut. Therefore, maintaining a healthy gut mucosa is vital to protecting the overall clinical status of a patient from further compromised immune function.
Although other reasons may account for an individual's nutritional demise, diminished food intake is often overlooked as a key factor. Pain, queasiness, nausea/ vomiting, overwhelming fatigue, weakness, and negative response to food or liquids may be as crucial as the treatment effects of the disease as the reason for inadequate intake. Therefore, an assessment method that will capture the problems and identify the patient's limitations is essential to effective patient management.
Quality of life, activities of daily living, and functional status are important areas of screening/assessment that are gaining recognition. Each clinician and every health-care facility will need to acquire a measurement tool or a screening form that captures these issues. By identifying areas of limitation or incapacity, the health-care professional can provide assis tance, support, or other means of care for the individual who is unable to function adequately and hence has potential for limited nutritional intake.
Another area that should be included in a successful nutrition screening/assessment is the individual's use of complementary therapies and supplements. Cancer patients are especially susceptible to the use of unconventional modalities if a possible edge or advantage is believed to be attainable. Discussing the possible risks/ benefits of a given therapy with the patient will not only provide invaluable information needed for the medical record, but will also open the channel of communication between the health professional and the patient.
Establishing Nutrition Goals
Therefore, the health professional should work with the patient and family or caregivers to establish nutrition priorities appropriate for the patient's current circumstance. New goals might include striving for adequate caloric intake, preserving functional status (including weight, skeletal muscle mass, and activities of daily living), and achieving adequate total nutrient intake. When nutritional goals are not being met, options for nutritional management should be provided. If at all possible, oral feeding should be attempted with either six small, nutrient-dense feedings, nutrient-dense drinks to augment meals, or other therapeutic oral regimens. When oral intake is inadequate regardless of attempts to achieve a reasonable intake, then enteral management should be implemented before further deterioration occurs.
Selecting patients who should be placed on enteral feedings should be based on a number of concerns. The characteristics of appropriate vs inappropriate candidates are illustrated in the following table.
Once enteral support is underway, adequate calorie and protein needs may be met easily. If the gastrointestinal tract is unavailable or contraindicated for feeding, then total parenteral or peripheral parenteral nutrition might be necessary.
Finally, when nourishing a cancer patient with active disease, the concern about feeding the tumor vs feeding the host may arise. There is controversy over the benefit or the adverse effect of caloric restriction in patients who have active disease. One needs to consider finding the point at which weight loss does not depress immunocompetence and shorten life, yet does inhibit or reverse tumor growth The clinician must evaluate whether nutritional support or caloric deprivation enhances or diminishes the nutritional status of the patient.
Many technologic and pharmacologic advances have been made toward improving the overall wellbeing of the cancer patient, but much more research and knowledge is still needed to understand the metabolic and nutritional needs of this unique population. What are optimal caloric needs? What are the best protein/amino acid source? Which fats might benefit, and which may hinder, the patient's responses? Are there optimal levels for micronutrients and non-nutrient components? We will hopefully seek and find answers in the coming years.