Metformin use may decrease the risk of grade progression in patients with non-muscle invasive bladder cancer (NMIBC), according to study findings presented at the Canadian Urological Association 2016 annual meeting in Vancouver.
Samer L. Traboulsi, MD, and colleagues at McGill University Health Centre in Montreal conducted a retrospective analysis of 1,356 NMIBC patients with a median age of 69.5 years. The cohort consisted of 1,197 patients (88.3%) without diabetes, 93 patients (6.9%) with diabetes on metformin, and 66 patients (4.9%) with diabetes and not on metformin who served as a reference group.
In multivariate analysis, metformin use was not associated with disease recurrence and stage and disease progression, but it was associated with a significant 68% decreased risk of grade progression compared with the reference group. In addition, patients without diabetes had a significant 42% lower risk for disease progression compared with the reference group.
Metformin is hypothesized to have antineoplastic activity due to its inhibitor activity on mammalian target of rapamycin, the researchers explained in a poster presentation.
“Investigations in clinical trials are needed to show whether metformin mitigates the deleterious effect of diabetes on stage progression,” Dr. Traboulsi’s group concluded.
Previously, in a paper published in Urologic Oncology (2015;33:386.e7-386.e13), Canadian researchers reported on a study of 421 patients undergoing radical cystectomy for bladder cancer showing that metformin users had a 62% decreased risk of disease recurrence and 43% decreased risk of death from bladder cancer. The study, which was led by Madhur Nayan, MD, of the University of Toronto, included 85 patients (20%) with diabetes, of whom 39 (46%) were on metformin.
See more coverage from the Canadian Urological Association’s meetings.