Selenium 200 mcg/d - studies show low selenium associated with increased risk of bladder cancer. Don't exceed 400 mcg/d as too much selenium is not good either.
Vitamin D as discussed before - most of my patients are low and it usually takes 5,000 IU/d to get most patients up where they should be, a blood level around 50 or better. Look up grassrootshealth dot org for more info about vit D and cancer
Cannabinoids - found in cannabis oil (made to be lower in tHC, the thing that gets you high, and higher in cannabinoids) - has lots of research suggesting it can be helpful in cancer, and there is lots of specific research on cannabinoid receptors in the bladder. If medical marijuana is legal in your state, I'd investigate this as well.
