Efficacy of Glutamine in the Prevention of Acute Radiation Enteritis

Background: Acute radiation enteritis is a common adverse effect related to radiotherapy (RT). Glutamine is an immune modulator and antioxidant amino acid that can exert a protective role in patients receiving abdominal or pelvic radiation. The aim of this study was to test if glutamine prevents radiation enteritis during RT. Materials and Methods: Double‐blind, randomized, controlled trial including 69 patients who needed RT because of pelvic or abdominal malignancies and received glutamine (30 g/d) or placebo (casein, 30 g/d). Enteritis was evaluated according to the Radiation Therapy Oncology Group scale, intestinal inflammation using fecal calprotectin, and gut integrity with citrulline. The incidence of enteritis was analyzed by Kaplan‐Meier curves, and the hazard ratio (HR) was calculated using Cox regression. Results: Patients were predominantly male (65.2%), with an average (SD) age of 66.6 (9.9) years, with urologic (44.9%), rectal (24.6%), or gynecological cancer (23.1%). More patients developed enteritis with glutamine than with the placebo (55.9% vs 22.0%; P = .002), with an HR of 1.59 (95% confidence interval, 0.62–4.05). There were no differences in final calprotectin levels (glutamine, 57.9 85.8] mg/kg vs placebo, 54.0 57.7] mg/kg; P = .182) or the number of patients with values >50 mg/kg (glutamine, 58.1% vs placebo, 54.6%; P = .777). Final citrulline levels were similar between groups (glutamine, 26.31 10.29] mmol/L vs placebo, 27.69 12.31] mmol/L; P = .639), without differences in the number of patients with <20 mmol/L (glutamine, 24.1% vs placebo, 25.0%; P = .938). Citrulline concentration was reduced during RT with placebo but remained unchanged with glutamine. Conclusion: Glutamine does not prevent the development of enteritis during RT.