Outcomes following radical cystectomy for micropapillary bladder cancer versus pure urothelial carcinoma: a matched cohort analysis

Micropapillary (MP) bladder cancer is a rare variant of urothelial carcinoma (UC) which has been associated with an aggressive natural history. We sought to report the outcomes of patients with MP bladder cancer treated with radical cystectomy (RC) and compare survival to patients with pure UC of the bladder. We identified 73 patients with MP bladder cancer and 748 patients with pure UC who underwent RC at our institution with median postoperative follow-up of 9.6 years. MP patients were stage-matched 1:2 to patients with pure UC. Survival was estimated using the Kaplan-Meier method and compared with the log-rank test. MP cancers were associated with a high rate of adverse pathologic features, as 48/73 patients (66 %) had pT3/4 tumors and 37 (50 %) had pN+ disease. Ten-year cancer-specific survival in MP patients was 31 %, compared with 53 % in the overall cohort with pure UC (p = 0.001). When patients with MP bladder cancer were then stage-matched to those with pure UC, no significant differences between the groups were noted with regard to 10-year local recurrence-free survival (62 vs. 69 %; p = 0.87), distant metastasis-free survival (44 vs. 56 %; p = 0.54), or cancer-specific survival (31 vs. 40 %; p = 0.41). MP cancers are associated with a higher rate of locally advanced disease. However, when matched to patients with pure UC, patients with MP tumors did not have increased local/distant recurrence or adverse cancer-specific survival following RC.