A single-institute experience of trimodal bladder-preserving therapy for histologic variants of urothelial carcinoma.

Background: We retrospectively evaluated the clinical outcomes of patients with histologic variants of muscle invasive bladder cancer (MIBC) treated with trimodal bladder-preserving therapy (TMT).

Methods: Among 148 patients with clinical T2-3N0M0 MIBC treated with TMT at Tsukuba University Hospital from 1990 to 2015, 11 patients (7.4%) had pathological components of variant urothelial carcinoma (UC). The complete response (CR), overall survival (OS), cause-specific survival (CSS) and progression-free survival (PFS) rates were analyzed in these 11 patients.

Results: Among the 11 patients with variant UC, 7 (64%) had UC with squamous and/or glandular differentiation and 4 (36%) had sarcomatoid (n = 1), plasmacytoid (n = 1), signet ring cell (n = 1), or clear cell variant (n = 1). Median follow-up was 49.0 months. Nine (82%) out of 11 patients achieved CR and 2 (22%) out of the 9 developed recurrence. Among seven patients who had UC with squamous and/or glandular differentiation, two developed recurrence and one died of disease. In contrast, 2 (50%) out of four patients with other variants, which were sarcomatoid variant or signet ring cell, developed recurrence and died of disease. Overall, the 5-year OS, CSS, and PFS rates of variant UC were 75%, 75%, and 58%, respectively.

Conclusions: TMT might provide acceptable clinical outcomes for well-selected MIBC patients with histologic variants, especially for those with squamous and/or glandular differentiation. However, we need to pay special attention to other variants such as sarcomatoid variant or signet ring cell. TMT might be an alternative treatment option for patients with histologic variants, although further experiments will be needed to confirm this.