My husband has been taking Metformin for 12 years. He has always been a non-smoker and pretty healthy -- plus cancer does not run in his family. Last August (2013) he started urinating blood. Sure enough, the urologist said he has bladder cancer. He had surgery in December to remove several tumors and by March 2014 when he went in for his 3 month checkup, he had more tumors. Tomorrow we start BCG treatment and we both are very scared. I feel that the Metformin is the contributing factor to his bladder cancer -- which he stopped taking in March. I would be interested to know just how many people with bladder cancer has taken Metformin.