Impact of divergent differentiation in urothelial carcinoma on oncological outcome in patients with T1 high-grade bladder cancer

Abstract

Objective: T1 high-grade bladder cancer has a poor prognosis compared with other non-muscle-invasive bladder cancers. We investigated the clinical outcomes among patients with T1 high-grade bladder cancer to identify factors related to cancer recurrence and disease progression.

Methods: We retrospectively reviewed the data of 148 patients who were diagnosed with T1 high-grade bladder cancer by transurethral resection from January 2001 to February 2015 at our institution. Clinicopathological factors were analyzed using univariate and multivariate analyses.

Results: The median age and follow-up duration were 72 years and 45.4 months, respectively. Sixty-two patients (41.9%) had recurrence, 28 (18.9%) experienced progression and 13 (8.8%) died of bladder cancer. In the multivariate analysis, divergent differentiation was an independent factor related to recurrence (P = 0.0096, hazard ratio = 2.5), whereas a non-papillary tumor shape, divergent differentiation and presence of a residual tumor at the time of the second transurethral resection were independent factors related to progression (P = 0.0349, hazard ratio = 3.8; P = 0.0074, hazard ratio = 6.8 and P = 0.0449, hazard ratio = 4.1, respectively). There were no independent factors related to cancer-specific mortality. Divergent differentiation was the only independent factor associated with both recurrence and progression. In addition, patients with divergent differentiation had significantly worse recurrence-free survival and progression-free survival rates than did patients without divergent differentiation (log-rank P = 0.0009 and P = 0.0019, respectively).

Conclusions: In this study, the presence of divergent differentiation was related to worse oncological outcomes in patients with T1 high-grade bladder cancer. Patients with divergent differentiation may require stringent follow-up and early cystectomy after recurrence to improve oncological outcomes.

Keywords: T1; divergent differentiation; high grade; non-muscle-invasive bladder cancer; urothelial carcinoma.