Sarahlee,
When I asked Dr. Lamm (noted BCG expert) if my severe arthritic reaction meant that the BCG was doing it's thing, his answer to me was "It MIGHT be indicative" that BCG was being effective in fighting the bladder cancer.
Sometimes I will read a post here where a Uro has told his patient that bad side effects means that the BCG is working, but, after the way Dr. Lamm responded to my question, I interpret this to mean that they don't really know if it's a good sign or not. I sure do hope that I didn't go through all I went through for nothing.
I just don't know if there is a firm answer to this question, Saralee..
Rosemary