Parenteral versus enteral nutrition in cancer patients: indications and practice

Abstract

Prospective randomly controlled trials have failed to demonstrate the clinical efficacy of providing nutritional support to most cancer patients in terms of morbidity, mortality, and duration of hospitalization. Serious shortcomings in study design have limited the possibility of drawing definitive conclusions from the data. Thus, nutritional intervention needs to be seen as a method of support, with the aim of maintaining nutritional and functional status during the stress of the oncology treatment to prevent or attenuate cachexia. There is no disease during which the patient benefits from prolonged wasting. Pretreatment weight loss is quoted as a major indicator of poor survival and response to therapy of cancer patients. As a consequence, an early and serial assessment of nutritional status, perhaps followed by an immediate intervention with nutritional support is strongly recommended. There are other specific reasons for using the gut rather than the intravenous route for nutrient administration besides the often reported disadvantage of significant cost. Local intestinal stimulation prevents the mucosal atrophy and bacterial translocation that can be triggered by several precipitating factors, as frequently seen in oncologic patients. These include endotoxin, radiation therapy, cytotoxic and immunosuppressive drugs, cytokines, bowel and biliary obstruction, broad-spectrum antibiotics, and the tumour itself, as well as parenteral nutrition (PN). As the enteral route of nutritional support has been found to be as good as or preferable to PN in terms of maintenance of nutritional status or immune function, prevention of bacterial translocation, maintenance of normal gut flora, transit and histology, and prevention of hypercatabolic responses to stressful events, it is always preferable in terms of physiological response, local and systemic competence, quality of life and cost, and should be the method of choice for the nutritional support of cancer patients. Although retrospective studies of PN suggest a benefit for patients with cancer who are undergoing surgery, radiation, or chemotherapy, carefully designed, prospective studies report less conclusive findings. The failure of conventional PN to improve clinical outcomes in patients with cancer may be related to the fact that standard formulations do not address or reverse abnormalities of intermediate metabolism that result in cancer cachexia. Supplemental substances have been proposed in an attempt to improve the efficacy of PN, including insulin, growth hormone and branched chain amino acids. The difficult task is to identify those patients who are at risk for malnutrition and at the same time identify the subset of patients who will benefit clinically from parenteral nutritional repletion. Severe malnutrition in patients requiring surgery, bone marrow transplantation in patients unable to tolerate enteral supplementation and postoperative complications necessitating nutritional support are specific indications. Routine use of PN should be discouraged.

Complications for Radical Cystectomy

“…While indiscriminate use of postoperative total parenteral nutrition or enteral feeding is unwarranted [10], preoperative nutritional support should be implemented in cancer patients with malnutrition [11]. In this respect, the recent report in digestive tract cancer surgery of beneficial preoperative feeeding with supplemented enteral formula followed by postoperative jejunal feeding [12]might pave the way for similar minimally invasive support in malnutrition bladder cancer patients.…”

Endoscopic Palliation and Nutritional Support in Advanced Gastric Cancer

“…Cancer is the most common indication for the use of TPE as a method used for the delivery of nutrients directly into the blood, bypassing the decreased food intake and dysfunction of the gastrointestinal tract [57] . TPE has been shown to be appropriate for malnourished cancer patients receiving aggressive anticancer treatment, and to have a permissive role in those patients who cannot be given oncologic therapy because of a poor nutritional status.…”

“…TPE should be reserved for patients with gastrointestinal tract dysfunction due to an obstruction, peritoneal carcinomatosis, surgery, high output fi stula, fi brosis or major intestinal resections, who have a reasonable prognosis and cannot tolerate enteral feeding [57] . This category of patients can benefi t from long-term TPE at home, with TPE-related complications comparable to those seen in benign diseases.…”

What We Have Learned about Cachexia in Gastrointestinal Cancer

“…However, several large studies showed that this drug has no significant impact on weight gain or any other benefit in patients with advanced colorectal cancer [120][121][122]. Increased survival times, improved appetite and increases in caloric intake and serum albumin levels have been reported with the use of hydrazine sulfate in some studies, but these favorable effects have not been confirmed by others [79]. Because of the lack of definitive studies showing consistent efficacy, together with the significant risk of neurotoxicity associated with its use, this drug has not gained popularity with oncologists [2,80].…”

“…Finally, controversy remains regarding the influence of aggressive nutritional support on the quality of life of patients with advanced cancer, and it is very important to consider the risks, benefits and ethical aspects involved before beginning such a regimen. Physician attitudes, patient age and prognosis, and family or patient's perceptions often play important roles in the decision to administer nutritional support, and these variables will continue as issues during the patient's course [79].…”