Glutamine and its use in selected oncology settings

Abstract

This review summarises the latest evidence for the use of glutamine (GLN) in  oncology taking cognisance of current systematic reviews and available guidelines. Various studies in adults suggest that GLN supplementation suppresses tumour  growth, by restoring the function of natural killer cells; improves protein metabolism; and, possibly enhances the effect of cancer therapy. There is insufficient data on whether GLN supplementation reduces the incidence of infection, although a trend exists towards such a reduction. GLN-supplemented enteral nutrition was superior in improving immune function, whilst oral GLN alone appeared to have no effect on: mortality; infections; time to neutrophil recovery; or, relapse. GLN significantly reduces the duration of diarrhoea, but had no effect on its prevention. Oral GLN may reduce the duration and severity of mucositis, with fewer days on opioid therapy. Oral GLN, but not intravenous GLN (IV-GLN), may decrease mucositis and graft-versus-host disease in adult bone marrow transplant patients. Currently, the  evidence for reduction of severe mucositis or infection rate in children is not statistically significant, but GLN does significantly reduce parenteral nutrition use, reflecting a possible improvement in lower gut mucositis. Nevertheless, too few studies exist to either support or refute that GLN supplementation either reduces the duration of, or prevents the progression to, severe mucositis. In children, there is no significant evidence that IV-GLN supplementation reduces infection rates, hospital length of stay (LOS), graft-versus-host disease, or mortality. Children with solid tumours on chemotherapy receiving oral GLN supplementation showed  significant improvements in some nutritional and immunological parameters, as well as the severity of stomatitis and need for antibiotic therapy. Caution is  recommended when considering provision of IV-GLN to oncology patients who have hepatic or renal insufficiency or failure. Monitoring of hepatic and renal function is recommended. Further studies are needed specifically on the use of glutamine in an oncology setting. Larger, multicentre, randomised placebo-controlled studies are needed in both adult and paediatric oncology populations.

Keywords: cancer, glutamine, mucositis, oncology