Flow Cytometry as a Predictor of Response and Progression in Patients with Superficial Bladder Cancer Treated with Bacillus Calmette-Guerin

Abstract

Simultaneous bladder wash flow cytometry, voided urinary cytology, and cystoscopic examinations were performed at 3-month intervals during a median of 18 months (range 5.5 to 50 months) in 65 patients receiving intravesical bacillus Calmette-Guerin treatment for superficial bladder cancer. Of the 65 patients treated 36 (56 per cent) had a complete response, 12 (18 per cent) had no response and 17 (26 per cent) had progression. Results of examinations at 6 months suggested that a negative bladder wash flow cytometry (29 of 36 patients, r equals 0.73, p less than 10-7) is a strong predictor of response to bacillus Calmette-Guerin, comparable with cytological (r equals 0.60, p less than 10-7) or cytoscopic (r equals 0.38, p less than 0.005) examinations alone or combined with cytology (r equals 0.74, p less than 10-7). At 6 months a positive bladder wash flow cytometry (r equals 0.44, p less than 0.0005) is as strong a predictor of disease progression as a positive cystoscopic examination (r equals 0.43, p less than 0.0005). The combination of bladder wash flow cytometry and voided urinary cytology is not superior to positive bladder wash flow cytometry alone. Median estimated interval to progression for these patients treated with bacillus Calmette-Guerin was 38 months. In the subgroup with positive bladder wash flow cytometry at 6 months the median interval to progression was 30 months. With a negative bladder wash flow cytometry at 6 months the probability of survival free of progression at 30 months was 85 per cent (p less than 0.01). Thus, negative bladder wash flow cytometry at 7 months is a strong predictor of response to bacillus Calmette-Guerin and also survival free of progression.