2391P - Impact of perioperative chemotherapy on survival and pathological stage in muscle-invasive micropapillary urothelial bladder cancer

Background

Micropapillary urothelial carcinoma (MUC) is a rare and aggressive histological variant with poor clinical outcomes and limited consensus regarding its management. The mainstay of treatment in muscle-invasive disease is radical cystectomy (RC). Data regarding the role of neoadjuvant chemotherapy (NAC) and adjuvant chemotherapy (AC) in muscle-invasive MUC is limited.

Methods

The United States National Cancer Database was queried for patients (pts) with MUC diagnosed from 2004 to 2018. Pts older than 18 years with cT2-4aN0-1M0 MUC who underwent RC were included. Clinical T4b/N2-3/M1 and receipt of NAC+AC were used as exclusion criteria. The pts were divided into three cohorts based on perioperative therapy- NAC, AC, and no chemotherapy (CX^-). Chi-Square and Kruskal-Wallis tests were used to compare frequency distributions. Cox Proportional Hazards regression was employed to adjust for confounders associated with overall survival (OS). Models were adjusted for age, race, sex, stage, insurance, and comorbidities.

Results

Of the 477 pts included, 80% were males, and 93% were White. 103 (21.6%) and 157 (32.9%) received NAC and AC, respectively, while 217 (45.5%) belonged to the CX^- group. Pts in the NAC & AC groups were younger (66 yrs vs 73 yrs in CX^-, p<0.001). OS was longer in the NAC and AC groups (Table). However, on multivariable analysis, NAC was predictive of OS (Hazard Ratio (HR) 0.68, 95% CI 0.47-0.97, p = 0.03) while AC was not (HR 0.84, 95% CI 0.63-1.12, p =0.22). In a separate Cox model, pT0-1N0 disease was independently associated with improved OS (HR 0.27, 95% CI 0.12-0.61, p=0.002). The NAC group had significantly more pT0N0 (14.8% vs 2.8%, p<0.001) & pT0-1N0 (21% vs 5.9%, p<0.001) disease at RC compared to the combined cohort of AC+CX^-.

Table: 2391P

Conclusions

In this large retrospective analysis, NAC was independently predictive of longer OS in muscle-invasive MUC, while AC was not. NAC was also associated with pathological downstaging.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

A.M. Roy.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.