Oncologic outcomes of neoadjuvant chemotherapy and lymph node dissection with partial cystectomy for muscle-invasive bladder cancer

Background: Partial cystectomy (PC) offers potential benefits for select patients with muscle- invasive bladder cancer (MIBC). However, the oncologic efficacy of PC may be compromised due to the underutilization of standard-of-care modalities, such as neoadjuvant chemotherapy (NAC) and pelvic lymph node dissection (PLND). We aimed to assess factors influencing the incorporation of NAC and PLND with PC and evaluate their impact on overall survival (OS). Methods: We identified 2,832 patients with cT2-4N0M0 bladder cancer (BCa) who underwent PC between 2004 and 2019 using the National Cancer Database (NCDB). The primary endpoint was OS. Kaplan-Meier analysis compared OS in treatment modalities in PC patients. Multivariate Cox Proportional Hazards (CPH) model assessed the impact of age, sex, race, insurance, income, Charlson-Deyo Index (CDI), clinical T-stage, facility type, histology, surgical margins, NAC, PLND adequacy [>= 10 lymph node (LN) yield], and adjuvant radiation treatment on OS. Multivariate logistic regressions were performed to examine predictors of NAC and PLND receipt in PC patients. Results: Two hundred and thirty-one patients received multi-agent NAC with PC. NAC treatment with PLND was associated with significantly improved OS (P<0.001). Median OS was 43.9 months in patients treated with PC alone, while median OS was not reached in PC patients treated with NAC & PLND. Furthermore, patients who received NAC without any PLND had a median OS of 50.6 months, while those treated with PLND without NAC had a median OS of 76.5 months. This persisted in the adjusted CPH model, where private insurance, NAC, and PLND significantly improved OS, especially when PLND yielded >= 10 LN. Conversely, age >80 years old, CDI >2, cT3-4, positive margins, and adjuvant radiation all increased adjusted mortality risk. After controlling for clinicopathologic variables, females were less likely to receive PLND [odds ratio (OR) 0.719, P=0.005], while NAC was more likely administered to PC patients diagnosed from 2016-2019 (OR 5.295, P<0.001). PC patients who received NAC were more likely to have PLND performed as part of their treatment regimen (OR 2.189, P<0.001). Additionally, patients treated at academic centers were more likely to have NAC administered and PLND performed (OR 1.745, P=0.003; OR 2.465, P<0.001, respectively). Conclusions: Despite guideline recommendations, the utilization of NAC and PLND with PC remains insufficient. Our analysis underscores the significant OS benefit of these recommended treatments as part of MIBC care. Importantly, we highlight a gradual increase in NAC and PLND receipt in recent years, centered largely at academic facilities. Notably, gender disparities exist in PLND receipt, emphasizing the need for further investigation.