It is important to remember that, in most cases, no cause for bladder cancer (or many other cancers) is ever found for a particular patient. Your urologist is correct in that smoking and industrial chemical exposure are among the factors that HAVE been found to be related to bladder cancer incidence. However, for most of us, we will never know. I am one of many who never smoked.
There are lots of studies on the possible relationship of Metformin use and multiple cancers. I haven't read any that are truly convincing. There are as many that purport to show a protective effect for Metformin in bladder cancer as there are those that suggest it as a cause. And all of these studies in humans are of the type that combine data from other studies in the literature....not original research. Interesting but not truly indicative.
Your mental energy now is needed to beat this...and you CAN!! Trying to figure out what caused it is not going to be productive when the evidence is so contradictory AND it would do nothing to help with this battle.
Wishing you the best
Diagnosis 2-08 Small papillary TCC; CIS
BCG; BCG maintenance
Vice-President, American Bladder Cancer Society
I had been taking metformin for many years prior to being diagnosed with bladder cancer. In 2013 I began to have frequent and urgent urination that progressively worsened. Several months later I began to pass blood in my urine, at which time, I realized I had a serious problem. I made an appointment with a Urologist for a cystoscopy, and discovered that I had 5 cancerous tumors in the upper portion of my bladder. I went through 6 weeks of BCG treatments which were very successful. However, several months later, after another followup cystocopy, 2 more tumors had developed in middle potion of bladder. Again, I went through another round of BCG that got rid of those 2. In the latter part of 2015 after another followup cystocopy, 1 very aggressive tumor had developed in the neck of bladder that had metastacized in to the prostate. July of 2016 I underwent surgery to have bladder and prostate removed. I'm convinced that all this was the result of my taking metformin for so many years. My urologist had informed me that smoking, working with chemicals and artificial sweetners were the main causes of bladder cancer, which I never did any of those.