Nutrition plays a major role in many aspects of cancer development and treatment. Malnutrition is a common problem in cancer patients that has been recognized as an important component of adverse outcomes, including increased morbidity and mortality and decreased quality of life. Weight loss has been identified as an indicator of poor prognosis in cancer patients. It has been shown that at the time of diagnosis, 80% of patients with upper gastrointestinal cancer and 60% of patients with lung cancer have already experienced a significant weight loss, generally defined as at least a 10% loss of body weight in 6 months' time. Good nutrition practices can help cancer patients maintain weight and the body's nutrition stores, offering relief from nutrition impact symptoms and improving quality of life. Poor nutrition practices, which can lead to undernutrition, can contribute to the incidence and severity of treatment side effects and increase the risk of infection, thereby reducing chances for survival. Nutrition impact symptoms are those symptoms that impede oral intake. They include, but are not limited to, anorexia, nausea, vomiting, diarrhea, constipation, stomatitis, mucositis, dysphagia, alterations in taste and smell, and pain. Early recognition and detection of risk for malnutrition through nutrition screening followed by comprehensive assessments is increasingly recognized as imperative in the development of standards of quality of care in oncology practices.
Goals of Nutrition Therapy
Optimal nutritional status is an important goal in the management of individuals diagnosed with cancer.
The goals of nutrition therapy are to accomplish the following:
• Prevent or reverse nutrient deficiencies.
• Preserve lean body mass.
• Help patients better tolerate treatments.
• Minimize nutrition-related side effects and complications.
• Maintain strength and energy.
• Protect immune function, decreasing the risk of infection.
• Aid in recovery and healing.
• Maximize quality of life.
Patients with advanced cancer can receive nutritional support even when nutrition therapy can do little for weight gain.
Such support may help accomplish the following:
• Lessen side effects.
• Reduce risk of infection (if given enterally).
• Reduce asthenia.
• Improve well-being.
In individuals with advanced cancer, the goal of nutrition therapy should not be weight gain or reversal of malnutrition, but rather comfort and symptom relief.
Enteral Nutrition
The benefits of enteral nutrition, or tube feeding, are that it continues to use the gut, has fewer complications such as infection and organ malfunction, is often easier to administer, and is cheaper than parenteral nutrition. In addition, nutrients are metabolized and utilized more efficiently by the body.
Specific disease and condition-related indications for use consist of a diagnosis of a cancer of the alimentary canal (in particular, head and neck, esophageal, gastric, or pancreatic cancers) and severe complications/side effects from chemotherapy and/or radiation that are seriously jeopardizing the treatment plan of an individual already suffering from malnutrition.
Contraindications for enteral nutritional support include a malfunctioning gastrointestinal tract, malabsorptive conditions, mechanical obstructions, severe bleeding, severe diarrhea, intractable vomiting, gastrointestinal fistulas in locations difficult to bypass with an enteral tube, inflammatory bowel processes such as prolonged ileus and severe enterocolitis, and/or an overall health prognosis not consistent with aggressive nutrition therapy.
Parenteral Nutrition
Parenteral nutrition may be indicated in select individuals who are unable to use the oral or enteral route (i.e., those who have a nonfunctioning gut), such as those with obstruction, intractable nausea and/or vomiting, short-bowel syndrome, or ileus. Additional inclusive conditions common in the cancer population are severe diarrhea/malabsorption, severe mucositis or esophagitis, high-output gastrointestinal fistulas that cannot be bypassed by enteral intubation, and/or severe preoperative malnutrition.
Contraindications for use of parenteral nutrition are a functioning gut, a need for nutritional support for a duration less than 5 days, an inability to obtain intravenous (IV) access, and poor prognosis not warranting aggressive nutritional support.
Cancer Prevention Guidelines
The American Cancer Society (ACS) Guidelines for Nutrition and Cancer Prevention [29] first published in 1996 provide more detailed dietary advice with a focus on cancer prevention. These guidelines, updated in 1999, are consistent in principle with those recommended by the USDA and other organizations.
The ACS guidelines include the following:
• Choose most of the foods you eat from plant sources. Consume at least 5 servings of fruit and vegetables daily, as well as grain products such as cereals, breads, and pasta plus beans several times daily.
• Limit your intake of high-fat foods, particularly from animal sources. This is accomplished by choosing foods low in fat and cutting back on meat consumption.
• Be physically active: achieve and maintain a healthy weight. Be at least moderately active for 30 minutes on most days of the week. Stay within a healthy weight range.
• Limit consumption of alcoholic beverages, if you drink at all.
The American Institute for Cancer Research (AICR) published a report in 1997 [31] that includes an expert scientist panel review and evaluation of more than 4,500 studies on diet and cancer. The AICR Diet and Health Guidelines for Cancer Prevention were developed from these recommendations. The AICR also maintains a Web site that includes booklets of healthy recipes that follow their dietary guidelines.The AICR and ACS guidelines are similar.
The AICR guidelines include the following:
• Choose a diet rich in a variety of plant-based foods.
• Eat plenty of vegetables and fruits.
• Maintain a healthy weight and be physically active.
• Drink alcohol in moderation, if at all.
• Select foods low in fat and salt.
• Prepare and store food safely.
• Do not use tobacco in any form.
Indication
• Secondary Cancer
• Lung Cancer
• Prostate Cancer
• Breast Cancer
• Colon Cancer • Esophageal and Gastric Cancer
