Although the many benefits of achieving good nutritional status via nutritional support can clearly be detailed, the disadvantages or questionable benefits of nutritional support must also be considered. The debate regarding the effect of nutritional support on tumor growth has not been settled; though quality of life is usually improved with better nutritional status, the actual impact of nutritional support on longevity has yet to be definitively determined.
Once the degree of malnutrition has been assessed, the decision to offer nutritional support and which form of support to utilize must be determined by the healthcare professional and other parties involved. Enteral and parenteral nutritional support offers viable options to reduce the risk of debilitating malnutrition and interruptions in anticancer therapy that may influence outcome. Each form of nutritional support has advantages and disadvantages. It is critical to thoroughly evaluate the diagnosis, prognosis, degree of malnutrition, function of the gut, and ease of delivery before embarking on the plan of nutritional support. Caution must also be exercised to avoid refeeding syndrome, the metabolic complication that is caused by rapid repletion of potassium, phosphorous, and magnesium in a severely malnourished or cachectic patient.
The following sections highlight the benefits, contraindications, methods of administration, formulas, and home care issues for both enteral and parenteral 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.[26,27,28,29] 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. Thrombocytopenia and general pancytopenic conditions following anticancer treatments may also prevent placement of an enteral tube.
Several effective methods for the delivery of enteral nutritional support or tube feedings exist. An approximation of how long nutritional support will be needed is critical, however, to determine the most appropriate delivery route. Nasogastric, nasoduodenal, or nasojejunal methods are best for short-term support (<2 weeks). The endpoint of delivery—the stomach, the duodenum, or jejunum—is determined by the risk of aspiration, with nasojejunal feeds recommended for individuals with aspiration risk. If the person with cancer is at very high risk for aspiration, enteral nutritional support may be contraindicated and parenteral nutrition should be considered. Also, immune-compromised individuals with mucositis, esophagitis, and/or herpetic, fungal, or candidiasis lesions in the mouth or throat may not be able to tolerate the presence of a nasogastrointestinal tube.