Link bariatric and GLP-1 registries to cancer registries in every country that has both
Millions of people have had weight-loss surgery or now take weight-loss drugs. Linking those records to cancer registries would show, cancer by cancer, how much reversing obesity prevents, for almost no cost.
Nordic registries and the Cleveland Clinic SPLENDID cohort show about a third fewer obesity-related cancers after bariatric surgery, but individual sites (oesophageal adenocarcinoma, colorectal, pancreatic) are underpowered, and the emerging GLP-1 receptor agonist data are from insurance claims with short follow-up. Most high-income countries have national bariatric surgery registries, complete cancer registries and prescription databases; a federated linkage with a common protocol would produce site-specific, sex-specific estimates, detect any unexpected harm (post-bariatric colorectal cancer, thyroid), and provide the counterfactual against which GLP-1 drugs can be judged.
- Weak real-world evidence and registries · We do not reliably know what happens to patients after approval, so we cannot tell which drugs deliver in practice.
- Data silos · Records, scans, genomes and outcomes sit in separate systems that cannot talk. Every patient's experience is lost to the next.
- Prevention we already have is not deployed · Around four in ten cancers are preventable with tools we already own: vaccines, tobacco control, weight, alcohol, sun and infection control.