Is neoadjuvant chemotherapy for pT2 bladder cancer associated with a survival benefit in a population-based analysis?

Abstract

Background: Patients with organ confined muscle-invasive bladder cancer (MIBC) who are candidates for radical cystectomy (RC) should receive neoadjuvant chemotherapy (CHT). However, the most contemporary CHT use rates indicate low adherence to these guidelines. We tested contemporary neoadjuvant CHT rates and associated cancer-specific mortality (CSM) and overall mortality (OM) in pT2N0 MIBC patients treated with RC.

Materials and methods: Within the SEER database (2004-2015), we identified patients with pT2N0 MIBC patients who underwent RC. CHT administration rates were evaluated using estimated annual percentage changes (EAPCs) analyses. After inverse probability of treatment weighting (IPTW), Kaplan-Meier (KM) analyses and Cox regression models (CRMs) were used to test the effect of CHT vs no CHT on survival. Landmark analyses tested for immortal time bias.

Results: Of 3978 RC patients, 38.2% of patients received CHT. Between 2004 and 2015, CHT rates increased from 15.9% to 66.2% (EAPC: +14.2%; p < 0.001). IPTW-adjusted KM showed 10-year CSM-free survival rates of 78.9% for CHT vs 76.7% for no CHT patients (p = 0.6). Similarly, IPTW-adjusted KM showed 10-year OM-free survival rates of 54.6% for CHT vs 57.9% for no CHT patients (p = 0.8). In IPTW-adjusted MCRMs, CHT was not significantly associated with lower CSM (HR 0.97, CI 0.82-1.14; p = 0.7) or OM (HR 1.02, CI 0.90-1.16; p = 0.7). Virtually the same CSM and OM rates were recorded after landmark analyses.

Conclusions: CHT use in pT2N0 MIBC RC patients sharply increased over the study span. However, neoadjuvant CHT was not associated with better survival in this patient group.

Keywords: Bladder cancer; Cancer-specific mortality; Chemotherapy; Radical cystectomy; SEER program.