ASCO 2026: Real-World Data Tie GLP-1 Receptor Agonists to Lower Mortality in Multiple Solid Tumours

Multiple real-world analyses presented at the American Society of Clinical Oncology (ASCO) 2026 meeting suggest that glucagon-like peptide-1 receptor agonists (GLP-1RAs) are associated with lower mortality across several solid tumours — raising interest in potential oncology uses beyond their established roles in type 2 diabetes and obesity.

Key Real-World Findings

Dr Jess Paulus, Senior Director of Real-World Research at Harvard and a lead RWD and pharmacoepidemiologist at Ontada, presented an analysis of patients from the US Oncology Network examining GLP-1RA exposure and overall survival (OS). The study identified roughly 400 patients with a GLP-1RA prescription recorded in oncology medical records across six solid tumour types.

The investigators reported an almost 35% reduction in the rate of death for GLP-1RA users compared with non-users after applying several analytic approaches to control confounding. Paulus emphasized the consistency of the result across different methods while acknowledging residual bias is possible.

“This was robust. We tried two or three different approaches to confounding control. We know there's bias in this work, but regardless of what approach we took, we got basically the same answer,” Paulus said.

Biologic Rationale And Clinical Concerns

Paulus and colleagues noted plausible mechanisms for an anti-cancer effect: GLP-1RAs can reduce inflammation and glycaemic availability and may exert direct anti-proliferative effects on tumour cells. However, oncologists raised concerns about GLP-1RA–related weight loss in patients who already experience anorexia and cachexia, underlining the need to define which tumour types and clinical contexts could safely benefit.

“Anorexia is associated with so many cancer types, especially advanced ones, and so this just feels like a drug that is completely contraindicated in many cancers. I think we are a long way from understanding which patients would most benefit, but this is a really pressing clinical question,” Paulus added.

Supporting Studies

Two independent real-world analyses presented at ASCO echoed similar protective associations:

• Penn Medicine: A retrospective study of women aged 45–80 with BMI ≥25 reported a roughly 30% reduction in breast cancer incidence among GLP-1RA users; the association appeared independent of BMI.
• Cleveland Clinic (TriNetX database): In obesity-related solid tumours, investigators observed a ~34% reduction in mortality and reported that high tumour expression of the GLP-1 receptor (GLP-1R) independently predicted better survival, suggesting a possible direct receptor-mediated anti-tumour effect beyond systemic metabolic changes.

Limitations And Next Steps

All studies reported are observational and reliant on real-world data, which can be affected by confounding, selection bias and incomplete medication capture (notably, GLP-1RA prescriptions recorded only in oncology records for the Paulus analysis). The authors and commentators stress these findings do not establish causation and call for prospective trials and mechanistic studies to confirm benefit, identify which patients might profit most, and evaluate safety — particularly regarding weight loss in vulnerable cancer patients.

GlobalData analysts noted that, if confirmed, GLP-1RAs could represent a novel preventive or adjunctive strategy across multiple solid tumours. GlobalData has summarised ASCO highlights in a report and will host a webinar on 25 June with analysts Jack Cuthbertson and Selena Yu. Clinical Trials Arena is a GlobalData-owned brand.

Bottom line: Real-world signals are provocative and consistent across multiple datasets, but robust prospective and mechanistic studies are needed before GLP-1RAs can be recommended for cancer prevention or treatment.