Disparities In Male Vs Female Oncologic Outcomes Following Bladder Preservation: A Population-Based Cohort Study

Abstract

Bladder cancer incidence is greater in men than women. In surgical series, females have higher recurrence rates, disease progression and mortality following radical cystectomy (RC) compared to men. However, a pooled analysis of RTOG trimodality therapy (TMT) studies have not shown a difference in disease-specific survival (DSS) or overall survival (OS) based on sex. Our hypothesis is that there would be no difference in OS between men and women receiving TMT for treatment of muscle invasive bladder cancer in clinical practice. The National Cancer Database was queried for patients 18 years or older who were diagnosed with AJCC 7th edition clinical stage T2-T4aN0M0 muscle invasive urothelial bladder cancer (MIBC) between 2004 and 2016 that underwent RC or TMT. Patients were considered to have received TMT if they received 40-80 Gy of radiotherapy with concurrent chemotherapy following a TURBT. Multivariable Cox proportional hazards models, adjusting for age, race, comorbidities, type of treatment facility, and AJCC clinical stage, were used to determine whether sex was associated with risk of mortality for the TMT, RC, and combined cohorts. 3132 (17.5%) patients underwent TMT between 2004-2016 while 14,736 (82.5%) received RC. The rate of RC and TMT by gender remained relatively constant between 2004 – 2016. The odds of receiving TMT on multivariable analysis did not differ between men and women (p = 0.2591). Women who underwent TMT were older but had less comorbidities than men that received TMT. Both men and women were less likely to undergo TMT at academic/research programs or comprehensive cancer programs compared to community cancer programs (p<0.05). There was no association between sex and risk of death among those that received TMT (women versus men HR 1.00, 95% CI 0.90-1.12). Age (HR 1.03, 95% CI 1.02-1.04) and patients with 3 or more comorbidities compared to 0 (HR 2.04, 95% CI 1.58-2.64) were positively associated with the risk of mortality among patients that received TMT. Within the RC cohort, there was also no association between sex and overall survival, even when stratified by year (HR 0.97, 95% CI 0.91-1.02). Contrary to reports in the surgical literature about differences in oncologic outcomes for men and women who undergo RC, the NCDB does not demonstrate differences in overall survival, between men and women undergoing TMT for MIBC. TMT remains an important treatment option in both men and women with MIBC.