Surveillance Intensity in Intermediate Risk, Nonmuscle Invasive Bladder Cancer: Revisiting the Optimal Timing and Frequency of Cystoscopy.

Purpose: We sought to determine the optimal cystoscopic interval for intermediate risk, nonmuscle invasive bladder cancer.
Materials and Methods: A retrospective analysis of patients with intermediate risk, nonmuscle invasive bladder cancer (2010-2017) was performed and 3 hypothetical models of surveillance intensity were applied: model 1: high (3 months), model 2: moderate (6 months) and model 3: low intensity (12 months) over a 2-year period. We compared timing of actual detection of recurrence and progression to proposed cystoscopy timing between each model. We calculated number of avoidable cystoscopies and associated costs.
Results: Of 107 patients with median followup of 37 months, 66/107 (77.6%) developed recurrence and 12/107(14.1%) had progression. Relative to model 1, there were 33 (50%) delayed detection of recurrences in model 2 and 41 (62%) in model 3. There was a 1.7-month mean delay in detection of recurrence for model 1 vs 3.2, and a 7.6-month delay for models 2 and 3 (p <0.001 model 1 vs 2; p <0.001 model 2 vs 3). Relative to model 1, there were 8 (67%) and 9 (75%) delayed detection of progression events in model 2 and 3. There were no progression-related bladder cancer deaths or radical cystectomies due to delayed detection. Mean number of avoidable cystoscopies was higher in model 1 (2) vs model 2 (1) and 3 (0). Model 1 had the highest aggregate cost of surveillance ($46,262.52).
Conclusions: High intensity (3-month) surveillance intervals provide faster detection of recurrences but with increased cost and more avoidable cystoscopies without clear oncologic benefit. Moderate intensity (6-month) intervals in intermediate risk, nonmuscle invasive bladder cancer allows timely detection without oncologic compromise and is less costly with fewer cystoscopies.