Immunonutrition vs standard nutrition for patients with cancer.

The prevailing belief in the value of immunonnutrition has been questioned as different patient populations show variable responses ranging from no benefit or even harm to significant improvements in clinical outcomes. The subject of this invited review is a previously published meta-analysis that showed important benefits from the perioperative use of an immunonutrition formula (defined as nutrition therapy that contains specific immune-modulating agents) in a distinct population: adult patients with cancer undergoing an elective major surgical operation. Findings showed that use of an immunonutrition formula was associated with reduced infectious morbidity, anastomotic leakage, hospital length of stay, and postoperative complications compared with standard formulations. These benefits were seen after adjusting for bias and removal of older publications. Issues, such as dosing, duration of therapy, baseline nutrition status, content of specific immunomodulatory agents, and route of delivery that contributed to the beneficial response, were discussed. Little difference in response was seen between well-nourished and malnourished patients, but geographic differences were seen, with greater outcome benefits seen in studies originating from Europe than from Asia or the United States. The best results were seen when at least three agents (arginine, fish oil, and RNA nucleotides) were given, with the timing of the delivery occurring throughout the perioperative period. A review of this meta-analysis is warranted because it shows a consistent benefit from such therapy over 30 years of clinical research, provides a detailed subset analysis of related issues, and highlights its value in improving outcome in this patient population.