Metformin for the Prevention of Bladder Cancer Recurrence: Is it Effective?

BACKGROUND: Many methods have been used for preventing and reducing recurrences of bladder cancers. In recent years, some investigators have examined the use of metformin for this purpose. First lines of evidence have shown that metformin inhibits cancer cell growth and prevents cancer occurrence in patients with type 2 diabetes. OBJECTIVES: This study is designed to assess metformin usage in the prevention of bladder cancer recurrence after the trans-urethral resection of a bladder tumor (TUR-T). PATIENTS AND METHODS: In the present study, metformin was administered in the treatment of 32 patients with a history of bladder cancer, and their results were compared with those of 33 patients with bladder cancer recurrence (placebo group). Patients in the metformin group received 1000 mg metformin (2 tablets 500 mg) for 1 year. Frequency of tumor recurrence was calculated and compared with the placebo group. RESULTS: There was no statistical difference between the 2 groups with respect to the recurrence rate (P > 0.05). Although the recurrence interval was longer for the metformin group, this increase was not statistical significant (P > 0.05). Furthermore, tumor recurrence had no correlation with sex or the grade of the tumors. CONCLUSIONS: According to our findings, it seems that metformin has no considerable inhibitory effect on the recurrence rate of bladder cancer, but that it can delay tumor recurrence.