Cytological, histological, and clinical correlations in intravesical Bacillus Calmette-Guerin immunotherapy.

Bacillus Calmette-Guerin (BCG), an attenuated form of mycobacterium, has been used extensively for the immunotherapy of bladder carcinoma. BCG induces a granulomatous response in the bladder wall. The cytological features induced by BCG-immunotherapy in urines and bladder washes have been described in only rare articles. We evaluated cytologic specimens from 50 patients who received intravesical BCG for bladder carcinoma. Forty-three patients received BCG therapy in a single course, averaging to 6.3 weeks per patient, whereas seven patients received an average of 9 weeks therapy with 2 to 3 interruptions. A total of 93 voided urines (avg, 1.9/patient), 57 bladder washes (avg, 1.1/patient) and 64 biopsies (avg, 1.3/patient) were obtained in the 2-year and 8-month retrospective review from these 50 patients. There were 30 responders and 20 nonresponders to BCG therapy. Positive cytology was predictive of recurrence: (cytologic-histologic correlation, 85%). Nine of 64 (14%) tissue biopsies revealed granulomatous inflammation, whereas only 2 of 150 cytological specimens (1.3%) exhibited specific inflammatory cells and epithelioid cells diagnostic of granulomas. Decoy cells appeared on the surface of the urothelium in four biopsies and in two cytological specimens. Based on this study, cytology appears to be adequate for the follow-up of BCG-treated patients for assessment of recurrence of carcinoma. Diagnostic features of granulomas were detected only in a smaller percentage of urine specimens, compared with biopsies. The presence of decoy cells in the urine and biopsies is an intriguing phenomenon that requires further investigation, especially in regard to the source of these cells and whether they are apoptotic in nature or whether they result from necrosis.