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, 0.624.05). 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.
Keywords: acute radiation enteritis; calprotectin; citrulline; glutamine; nitric oxide.