Let me start off by saying I am taking right now. But I too was very worried about this pill, but to be honest I was more worried about NOT taking it. It appears Metronidazole is the only cure with a 95% to work. You are taking it for 7 days. Im sure you smoke, use nutrisweet, certain toothpaste, something. Point is unfortunately almost everything these days has a possibility of cancer. Is it very likely..no not really BUT on the otherhand if you read up on Trish you are alot more likely to get other STD's or infections as well as being ALOT more likely to pick up HIV. My guess is the risks are alot more likely with not being treated that you would get HIV verse cancer with the pill. Also if worst came to worst as of now cancer is treatable, HIV is not.
The thing about medication is when they are doing trials if anything happens to someone it has to be listed. I once took an antibiotic that had a warning of possible death. So I called my Dr and she explained the above. So for cancer to be listed more then likely someone during trials was diagnosed with cancer and this had to be reported to the manufacture of the drug. So I would not worry about the cancer part.