Oncological outcomes of advanced muscle-invasive bladder cancer with a micropapillary variant after radical cystectomy and adjuvant platinum-based chemotherapy.

OBJECTIVE: To assess the oncological outcomes of radical cystectomy (RC) and adjuvant chemotherapy to treat muscle-invasive bladder cancer (MIBC) with a micropapillary component (MPC), and to compare outcomes with those from pure urothelial carcinoma (PUC).
MATERIALS AND METHODS: A retrospective review of clinicopathological and follow-up data was performed for all patients treated by RC and adjuvant platinum-based chemotherapy for advanced MIBC in three tertiary reference centers between 1999 and 2012. Uni- and multivariate Cox's regression analyses evaluated the association of the presence of MPC with disease recurrence and cancer-specific mortality.
RESULTS: Two hundred and thirty-five (88 %) PUC and 31 (12 %) MPC cases were included. Median age was 65 (39-83) years in the PUC group and 62 (45-80) years in the MPC group. Median survival was 29 months in the MPC versus 31 months in the PUC group. No significant difference was observed between the groups regarding main clinical and pathological characteristics. The median number of treatment cycles administered was 6 (3-8) in the PUC versus 5 (3-8) in the MPC group (p = 0.45). Five-year disease-free recurrence and cancer-specific survival (CSS) rates were 15 and 24 %, respectively, in the MPC versus 42 and 47 %, respectively, in the PUC group (p = 0.007 and 0.058). In multivariate analyses, ASA score, soft tissue surgical margins, and MPC were associated with disease recurrence (p = 0.022, 0.001, and 0.015, respectively). We found no association between MPC and cancer-specific mortality (univariate, p = 0.06).
CONCLUSION: MPC was associated with higher recurrence rates after RC and platinum-based adjuvant chemotherapy than that with pure urothelial tumors.