Indications for En Bloc Bladder Tumor Resection
En bloc resection should be performed for small bladder tumors less than 1 cm in diameter, where the entire tumor plus underlying bladder wall can be removed as a single specimen. 1, 2
Primary Indication: Small Tumors (<1 cm)
The most clearly established indication for en bloc resection is tumors with diameter less than 1 cm, where the complete tumor plus part of the underlying bladder wall can be resected as a single piece. 1 This technique ensures the specimen contains complete tumor tissue along with adequate bladder wall depth for proper pathological staging. 1, 2
Extended Indications Based on Recent Evidence
While guidelines specifically recommend en bloc technique for tumors <1 cm, emerging high-quality evidence supports expanding indications to tumors up to 3 cm:
A 2024 multicenter randomized phase 3 trial demonstrated that en bloc resection for tumors ≤3 cm significantly reduced 1-year recurrence rates (29% vs 38%, p=0.007) compared to standard piecemeal resection. 3
Subgroup analysis showed particular benefit for patients with single tumors, Ta disease, or intermediate-risk NMIBC when tumors were 1-3 cm. 3
A 2022 meta-analysis of 29 studies (4,484 patients) confirmed en bloc resection yields superior histopathological specimens with higher rates of detrusor muscle presence (pooled RR 1.31) and detectable muscularis mucosae (pooled RR 2.69). 4
Oncological Advantages Supporting Broader Use
En bloc resection provides critical pathological advantages that improve staging accuracy and treatment decisions:
Detrusor muscle sampling rates exceed 95-98% with en bloc technique versus 62% with conventional resection, ensuring accurate T-stage determination. 5, 4, 6
Residual tumor at repeat TURBT is significantly lower (7% vs 27.7%, p=0.01) after en bloc resection, indicating more complete initial tumor removal. 5, 4
Lamina propria invasion substaging is feasible in 68% of en bloc cases versus only 18% with conventional resection (p<0.001), allowing better risk stratification. 5
Safety Profile
En bloc resection demonstrates superior safety compared to conventional piecemeal resection:
Bladder perforation risk is dramatically reduced (pooled RR 0.13,95% CI 0.05-0.34). 4
Catheterization time and hospital stay are shorter following en bloc resection. 5
Immediate postoperative chemotherapy instillation is feasible in 100% of en bloc cases versus 91.5% with conventional technique. 5
Technical Considerations
For larger tumors (>1 cm), conventional fractional resection remains the guideline-recommended approach, resecting separately the exophytic portion, underlying bladder wall with detrusor muscle, and resection edges, with specimens sent in separate containers. 1, 2 However, the 2024 phase 3 trial evidence suggests this may be reconsidered for tumors up to 3 cm when en bloc technique is technically feasible. 3
Common Pitfalls to Avoid
Do not attempt en bloc resection for tumors >3 cm where complete single-piece removal is not technically feasible, as this may compromise complete resection. 3
Minimize cauterization during en bloc resection to prevent tissue destruction that compromises pathological evaluation. 1
Ensure adequate depth of resection into detrusor muscle regardless of technique chosen, as muscle presence in the specimen is mandatory for accurate staging. 1, 2