Will try to answer a your questions....and ask some of my own! First, you said that your husband had a "mild" form of bladder cancer? Never quite saw that adjective used to describe bladder cancer
Are you sure that it wasn't described as "low grade?" And then he was treated with BCG? Usually, BCG is NOT used for low grade bladder cancer unless it returns.
CIS (carcinoma in situ) is a form of transitional cell carcinoma that appears sort of like a rash on the bladder rather than a "mushroom-like" tumor, which is the other form. It is always considered high grade, which means that the cells are rapidly dividing and it has the potential to spread quicker than low grade. Here is a good explanation of CIS
bladdercancersupport.org/diagnoses/carcinoma-in-situ-cis-of-the-urinary-bladder.html
The treatment of choice for CIS which is still confined to the bladder lining is BCG. The usual protocol for this is to have BCG instillations once a week for 6 weeks, then for three weeks every three months until 2 years have passed. I was diagnosed with CIS and underwent this treatment and am now almost 9 years cancer-free! One of the reasons that BCG is normally not given with low grade bladder cancer that has not recurred is that the body does develop a sensitivity to it (that is what is supposed to happen) and, since it is not as effective in low grade, they are sort of "saving" the big guns for when it is really needed.
Has the urologist proposed a treatment plan for the CIS? This might be a really good time for your husband to seek a second opinion for a treatment plan at a center that treats LOTS of bladder cancer. CIS is treatable, but it is not something to fool around with.
Sara Anne