Cystitis post BCG

After 2 TURB and 12 BCG treatments, a cysto showed two red areas, not near the original cancer sites. A biopsy was done; the pathology was "Acute and Chronic Cystitis". The urologic oncologist said it was caused by the BCG treatments. At the next cysto exam, about 3 months later, no inflammed areas were seen. It has been 14 months since this happened. All cysto exams have been good.

I am a year and a half survivor - 1 TURB, 1 6 series of BCG and Interferon, 3 three series maintenance BCG and Interferon. Then this June the cysto revealed suspicion in the bladder but in an entirely different area of the bladder from the original tumor. Biopsy of the suspicious area revealed "atypical cells consistent with cystitis". My Dr. is away on vacation so this report is a read from one of his nurses. Some research seems to indicate that cystitis may be one of the side effects of intravesical chemical treatments. Does anyone have any experience with this? BTW, my Doc told me after the procedure to wait 2 to 3 weeks then make my appointments to proceed with my next maintenance series of BCG.

Any experience here would be welcome.