Impact of neoadjuvant chemotherapy on pathological stage and survival in sarcomatoid bladder cancer.

Abstract

530 Background: Sarcomatoid bladder cancer is an extremely rare and aggressive histological variant with poor prognosis and limited consensus regarding its management given rarity and lack of high-quality data. Radical cystectomy (RC) is the mainstay of treatment in muscle-invasive disease and adjuvant therapy is often offered to eligible patients with high-risk features. Data regarding the role of neoadjuvant chemotherapy (NAC) for this variant is limited. Methods: The National Cancer Database was queried to identify patients diagnosed with sarcomatoid bladder cancer from 2004 to 2018. Patients older than 18 years with cT2-4aN0-1M0 sarcomatoid bladder cancer who received curative-intent surgery were included in the analyses. Clinical T4b/N2-3/M1 disease and receipt of adjuvant chemotherapy were employed as exclusion criteria. The population was divided into two cohorts based on the receipt of NAC. Chi-Square and Mann Whitney U tests were used to compare frequency distributions. Cox Proportional Hazards regression was employed to adjust for confounding factors associated with overall survival. Models were adjusted for age, race, sex, income, stage, insurance status, and the Charlson Comorbidity Index. Results: A total of 573 patients were identified - 70% were males and 93% were White; 139 (25%) received NAC (NAC+) while 434 (75%) did not (NAC-). NAC+ patients were younger (65 vs 71 years, p < 0.001). Downstaging to pT0-1N0 at the time of RC was significantly more frequent in the NAC+ group compared to the NAC- group (32 (24.5%) vs. 28 (6.8%), p = 0.001). Overall survival (OS) was also significantly longer in the NAC+ group (median of 40.8 vs. 19.4 months, log-rank p = 0.003). On multivariable analysis, NAC+ (Hazard Ratio (HR) = 0.73, 95% CI 0.56-0.91, p = 0.02), pathological downstaging to pT0-1N0 (HR = 0.5, 95% CI 0.31- 0.8, p < 0.001), and any pathological upstaging (HR 4.1, 95% CI 1.5-6.6, p < 0.001) were independently associated with all-cause mortality, while other factors were not (Table). Conclusions: In this large retrospective analysis, administration of NAC in muscle-invasive sarcomatoid bladder cancer was associated with higher rates of downstaging to non-muscle-invasive disease at the time of RC and reduced all-cause mortality. [Table: see text]