Detrusor Muscle in TUR-Derived Bladder Tumor Specimens: Can We Actually Improve the Surgical Quality?

Introduction: Published series of transurethral resection of bladder tumor (TURBT) show high rates (18%-52%) of procedures resulting in no detrusor muscle (DM) layer being present in the pathologic specimen. This is of clinical importance since DM inclusion in surgical specimens is invariably associated with better oncologic results and is considered a surrogate marker of surgical quality. We sought to assess rates and predictors of DM absence (DM-) at a final pathology report in a series of consecutive TURBTs performed at a single tertiary-referral academic center. Materials and Methods: We retrospectively collected data from 437 TURBTs performed over 1 year. Complete endoscopic perioperative data were available for all patients; surgeons were categorized as either staff physicians or residents. Likewise, pathologic data, including tumor grade and stage, and DM status (present vs absent) were recorded. Only procedures with bladder cancer (BCa) at final pathology were included in the analyses. Logistic regression analyses tested potential predictors of DM-. Kaplan-Meier analyses were applied to assess the impact of DM- on postoperative tumor recurrence. Results: Overall, BCa was found in 302 (69.1%) specimens at final pathology; DM- occurred in 29 (9.6%) cases. A comparable rate of DM- was observed for procedures conducted by staff physicians and residents (9% [23/232] vs 12.8% [6/41], respectively; p=0.6). Flat morphology emerged as the most informative predictor of DM- after adjusting for tumor size, number of lesions, tumor stage and grade, surgeon experience, and resection modality. At Kaplan-Meier analysis, DM- was not associated with worse outcomes in terms of postoperative recurrence-free survival. Conclusions: Current findings showed a rate of roughly 10% of DM- at TURBT. Flat morphology emerged as the most significant predictor of DM-, whereas surgeon experience was not associated with DM-.