Overview
- The review combined 48 placebo-controlled randomized trials with 94,245 adults who had type 2 diabetes or excess weight, with a median follow-up of about 70 weeks.
- Compared with placebo, GLP-1 users had no difference in risk across 13 obesity-related cancers, with moderate certainty for breast, kidney, thyroid, and pancreatic cancers.
- Evidence for colorectal, liver, gallbladder, ovarian, endometrial, esophageal, multiple myeloma, and meningioma was low certainty, and the effect on gastric cancer was very uncertain.
- The trials evaluated FDA-approved agents such as semaglutide, liraglutide, dulaglutide, and tirzepatide, and none were designed to measure cancer outcomes as primary endpoints.
- Experts describe the findings as short-term reassurance and call for at least five years of follow-up in cancer-specific studies, while FDA cautions about medullary thyroid carcinoma for certain GLP-1s remain in place.