Oncologic Outcomes of cT1 and cT2 Micropapillary Variant Compared with cT1 and cT2 Conventional Urothelial Carcinoma Treated with Radical Cystectomy

Introduction:Our objective was to estimate the difference in outcomes for patients with clinical T stage 1 (cT1) and 2 (cT2) micropapillary (MPBC) and urothelial carcinoma (UCBC) bladder cancer treated with radical cystectomy (RC).Methods:We reviewed the National Cancer Database for patients with cT1/2N0M0 MPBC and UCBC treated with RC from 2004-2016. Patients were classified by cT stage and histology. Outcomes of interest included upstaging to advanced pathological stage (pT3/4), pathologically node positive disease (pN+), and overall survival (OS). The Kaplan-Meier method was used to estimate 5-year OS probability. Multivariable logistic regression models were fit to test for an association between cT stage and histology with outcomes.Results:We identified 23,871 patients, of whom 384 had MPBC and 23,487 had UCBC. More patients with cT1 and cT2 MPBC had advanced pathological stage and pN+ (cT1: 31% and 34%; cT2: 44% and 60%, respectively) compared with cT1 and cT2 UCBC (cT1: 18% and 14%; cT2: 27% and 24%, respectively). Compared with cT2 UCBC, patients with cT1 MPBC had similar odds of advanced pathological stage (OR: 0.96, 95% CI: 0.63-1.45, p=0.837) and increased odds of pN+ (OR: 1.62, 95% CI: 1.03-2.56, p=0.038). Five-year OS estimates for cT1 MPBC and UCBC were similar (58% and 60%, respectively) while cT2 MPBC had worse OS than cT2 UCBC (33% and 45%, respectively).Conclusions:In a cohort of patients undergoing RC, cT1/2 MPBC had worse outcomes than cT1/2 UCBC. Patients and surgeons should consider aggressive therapies for patients with cT1 MPBC due to the risk of inferior outcomes associated with cT2 MPBC disease.