Prospectİve Evaluatİon of Surgİcal Margİns İn Non-Muscle Invasİve Bladder Cancer Followİng Prİmary Transurethral Resectİon

Purpose: Non-muscle invasive bladder cancers (NMIBC) constitute approximately 75% of bladder cancer cases. Primary transurethral resection (TUR) plays a pivotal role in both diagnosis and treatment. However, despite initial resection, tumors are often missed, leaving behind microscopic residual tumors. This study aims to prospectively investigate the surgical margins of tumors, which may serve as a potential source of residual tumors. Methods: Seventy patients diagnosed with NMIBC who underwent primary TUR were enrolled in this study. Following initial resection, samples were collected from the normal-looking mucosa extending 1 cm beyond the surgical margins. Lesions were categorized as 'no tumor' for benign lesions, 'TCC' for urothelial cancer, and 'UD' for dysplasia. Clinical and pathological features of these groups were compared, and risk factors for detecting TCC in the normal-looking mucosa were analyzed. Results: The TCC group showed a significantly higher rate of T1 stage tumors compared to the no tumor group, and a significantly higher rate of high-grade (HG) stage tumors compared to the UD group. Moreover, the TCC group had a significantly higher proportion of high-risk patients (85.7%) compared to the other groups, while the no tumor group had a significantly higher proportion of low-risk patients (35.3%) compared to the TCC group (0.0%). Additionally, the TCC group demonstrated a significantly higher rate of carcinoma in situ (CIS) compared to the no tumor group (35.7% vs. 5.9%). TCC formation was associated with T1 stage, HG stage, and the presence of CIS based on univariate analyses. Conclusion: To minimize residual tumors and prevent recurrence in patients undergoing primary TUR, we advocate for resection of macroscopically visible tumors with at least 2 cm of intact bladder mucosa, thereby enhancing the quality of TUR.