Assessing treatment response after intravesical bacillus Calmette-Guerin induction cycle: are routine bladder biopsies necessary?

To determine the need for routine bladder biopsies (BBs) in assessing response to the induction cycle of intravesical bacillus Calmette-Guérin (BCG) for high-risk non-muscle-invasive bladder cancer (NMIBC). Our prospectively maintained NMIBC database was queried to identify patients with high-risk disease (carcinoma in situ, high-grade Ta/T1) who underwent BBs after BCG induction cycle. Urine cytology, cystoscopy, and BBs findings were evaluated. A total of 219 patients met the inclusion criteria. Urine cytology was positive in 20 patients and negative in 199; cystoscopy was positive in 35 patients, suspicious in 32 and normal in 152 patients. BBs yielded bladder cancer (BCa) in 43 (19.6%) patients, with a BCa rate of 9.3% in patients with negative cytology and cystoscopy as opposed to 38.0% in patients whereby one or both exams were suspicious/positive. The diagnostic accuracy of urine cytology, cystoscopy, and combined tests was 0.56, 0.70, and 0.71, respectively. The negative predictive value of combined tests was 90.7%. Performing BBs only in patients with positive cytology and/or positive/suspicious cystoscopy would have spared 140 (64%) patients to undergo this procedure while missing BCa in 13 (9.3%) of them, representing 30% of all BCa cases. Performing BBs only in patients with positive cytology and suspicious/positive cystoscopy would spare 64% of un-necessary BBs but miss a non-negligible number of BCas. While no data are available regarding the potential consequences of missing such BCas, such information should be taken into account in patient's counselling.

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