Role of partial cystectomy for muscle invasive bladder cancer: Impact on morbidity and overall survival, a population-based study, 2006-2017.

e16530 Background: National Comprehensive Cancer Network (NCCN) guidelines state partial cystectomy (PC) may be offered in select patients with clinical T2 (cT2) muscle invasive bladder cancer (MIBC) utilizing neoadjuvant chemotherapy (NAC) and pelvic lymphadenectomy (PLND). Our objective was to investigate utilization and survival outcomes of PC in a large contemporary cohort. Methods: Propensity matching was used to compare pathological and surgical outcomes in non-metastatic MIBC patients in the National Cancer Database undergoing PC or radical cystectomy (RC). Multivariate logistic regression was used to determine predictors of NAC, LND, peri-operative morbidity and mortality outcomes. This analysis was repeated in the subset with cT2 MIBC. Results: Of 31,306 T2-T4N0M0 patients, 1543 (4.9%) underwent PC. PC use was higher in older patients and most often (85%) performed for cT2 disease. The PC group was less likely to receive standard of care including NAC (11.4 vs 27.9%, p<0.001) and PLND (58.7 vs 92.5%, p<0.001) than the RC group. Pathological ≥T3 disease (pT3) was found in 39.4% and pos. nodes in 6.9% of PCs. Positive margins were higher in PC, 15.7 vs 10.6%, p<0.001. PC patients had shorter inpatient stay (4.2 vs 8.7 days, p<0.001), lower 30-day readmission (6.7 vs 9.6%, p<0.001), and decreased 30- and 90-day mortality (1.3 vs 1.8%, p<0.001 & 4.8 vs 4.9%, p=0.04). PC was an independent predictor of lack of NAC (OR 0.49, p<0.001) and PLND (OR 0.11, p<0.001), shorter LOS (b -4.66, <0.001), readmission rate (OR 0.72, p<0.001), and improved 30- and 90- day mortality (OR 0.55 & 0.75, p<0.001). In cT2 patients only: PLND and NAC were less utilized in PC (p<0.001), 32% were ≥pT3 and 6.6% node pos. In both full cohort and cT2 subset, PC was associated with slight improvement in time to mortality (Table) and overall survival (OS) (OR 1.44, p<0.001). Conclusions: PC is rarely used in treatment of MIBC. Despite guidelines, NAC and PLND are underutilized in PC. Care is required in selecting patients for PC as up to one third of cT2 patients have ≥pT3. In these likely highly selected patients, PC had lower peri-operative mortality and comparable OS to RC. Selection bias may play a role in these results and further investigation is needed to determine optimal candidates for PC.[Table: see text]