Substaging of pT1 Urothelial Bladder Carcinoma Predicts Tumor Progression and Overall Survival

Abstract

<b><i>Introduction:</i></b> Limitations in tumor staging and the heterogeneous natural evolution of pT1 urothelial bladder carcinoma (UBC) make the choice of treatment challenging. We evaluated if histopathological substaging (pT1a, pT1b, and pT1c) helps predict disease recurrence, progression, and overall survival following transurethral resection of the bladder (TURB). <b><i>Methods:</i></b> We included 239 consecutive patients diagnosed with pT1 UBC at TURB in a single institution since 2001. Each sample was interpreted by our specialized uropathologists trained to subclassify pT1 stage. Three groups were distinguished according to the degree of invasion: T1a (up to the muscularis mucosae [MM]), T1b (into the MM), and T1c (beyond the MM). <b><i>Results:</i></b> T1 substaging was possible in 217/239 (90%) patients. pT1a, b, and c occurred in 124 (57), 59 (27), and 34 (16%), respectively. The median follow-up was 3.1 years, with a cumulative recurrence rate of 52%, progression rate of 20%, and survival rate of 54%. Recurrence was not significantly associated with tumor substage (<i>p</i> = 0.61). However, the Kaplan-Meier survival analysis showed a significantly higher progression rate among T1b (31) and T1c (26%) tumors than T1a (13%) (log-rank test: <i>p</i> = 0.001) stages. In a multivariable model including gender, age, ASA score, smoking, tumor grade, and presence of carcinoma in situ, T1 substage was the single variable significantly associated with progression-free survival (HR 1.7, <i>p</i> = 0.005). Nineteen patients (9%) needed radical cystectomy; among them, 12/19 (63%) had an invasive tumor. Overall survival was significantly associated with tumor substaging (<i>p</i> = 0.001). <b><i>Conclusion:</i></b> Histopathological substaging of pT1 UBC is significantly associated with tumor progression and overall survival and therefore appears to be a useful prognostic tool to counsel patients about treatment options.