En bloc versus conventional resection of primary bladder tumor in terms of presence of detrusor muscle in biopsy specimen: a prospective study

Abstract Purpose Transurethral resection of bladder tumor (TURBT) is the crucial and standard approach in the diagnosis and management of urinary bladder cancer. This study compares conventional piecemeal and en bloc resection techniques in terms of detrusor muscle presence in resected specimens, surgical safety, and feasibility. Methods A prospective comparative study conducted from April 2024 to March 2025 included patients with up to three bladder tumors, measuring ≤ 3 cm, who were alternately assigned to undergo either conventional piecemeal resection or en bloc resection. The primary outcome was the presence of detrusor muscle in the resected specimen. Secondary outcomes included operative time duration, bladder perforation, and obturator reflex. The quality of tissue was assessed by pathologists using a Likert scale. Results Eighty-seven patients were included, 43 in the conventional and 44 in the en bloc group. The baseline characteristics and tumor size were comparable. Presence of detrusor muscle in specimens was higher in en bloc group (97.7% vs 83.7%; p = 0.030). Operative duration was shorter in the en bloc group (35.55 minutes vs 43.42 minutes; p = 0.001). A case of bladder perforation was observed in the conventional group. Pathologists observed better specimen orientation and architecture in the en bloc group. Presence of tumor in re-TURBT was 16.0% in the en bloc group and 28.6% in the conventional group (p = 0.497). Conclusions En bloc resection yielded a higher presence of detrusor muscle and shorter operative duration with better specimen quality compared to conventional piecemeal resection for tumor ≤ 3 cm.