Oncologic Outcomes of Robot-Assisted Radical Cystectomy for Variant Histology Bladder Cancer: A Multi-institutional...

Area of Science:

• Uro-oncology
• Surgical oncology
• Robotic surgery

Background:

• Variant histology (VH) bladder cancer presents aggressive characteristics and poor prognoses.
• Limited data exists on oncologic outcomes for VH following robot-assisted radical cystectomy (RARC).
• This study evaluates RARC outcomes for VH in a multi-institutional setting.

Purpose of the Study:

• To compare oncologic outcomes between variant histology (VH) and pure urothelial carcinoma (PUC) after robot-assisted radical cystectomy (RARC).
• To assess the feasibility and safety of RARC for VH.
• To identify factors influencing outcomes in VH patients undergoing RARC.

Main Methods:

• Retrospective analysis of 280 patients (60 VH, 220 PUC) undergoing RARC across 5 institutions.
• Propensity score matching (PSM) using 11 pretreatment covariates to balance baseline characteristics.
• Evaluation of perioperative, pathologic, and survival outcomes (DFS, CSS, OS).

Main Results:

• After PSM, perioperative outcomes were comparable between VH and PUC groups, except for a higher transfusion rate in VH.
• VH patients had significantly higher rates of advanced pathologic stage (≥ pT3 disease).
• Variant histology remained independently associated with significantly worse disease-free, cancer-specific, and overall survival, despite increased adjuvant therapy use.

Conclusions:

• Robot-assisted radical cystectomy is a feasible surgical approach for variant histology bladder cancer, with comparable perioperative outcomes to pure urothelial carcinoma.
• Variant histology is associated with more advanced disease and worse survival outcomes, irrespective of pretreatment factors.
• Close postoperative surveillance and multimodal systemic therapy are crucial for managing variant histology bladder cancer post-RARC.