GLP-1 receptor agonists during chemotherapy and radiotherapy: a supportive care call for nutrition-centred monitoring in the era of widespread prescribing

PURPOSE: To outline supportive-care considerations for using glucagon-like peptide-1 receptor agonists (GLP-1 RAs) during chemotherapy and/or radiotherapy, focusing on nutrition, body composition, and treatment tolerance. METHODS: This Comment addresses the supportive-care implications of this situation and draws on evidence from obesity trials, cardiovascular outcomes trials, pharmacokinetic studies, and oncology literature on sarcopenia and treatment tolerance. RESULTS: GLP-1 RAs improve cardiometabolic risk and, in selected high-risk populations, reduce major adverse cardiovascular events. However, body-composition studies indicate that their weight loss is not exclusively adipose; approximately 20-30% may be lean mass. In oncology, low skeletal muscle mass has been associated with higher rates of severe toxicity, more dose modifications, and worse survival. Delayed gastric emptying may lower maximum concentration and delay time to maximum concentration of oral co-medications while usually preserving overall exposure in non-oncology settings. CONCLUSION: Although GLP-1 RAs have preventive and cardiometabolic benefits, these do not exclude possible concerns during active cancer therapy. Systematic screening, dietetic support, resistance exercise, and body-composition monitoring should guide initiation or continuation decisions during active treatment.