Clinicopathological Characteristics and Survival Outcomes in Micropapillary Urothelial Carcinoma of the Bladder — Expert Commentary

Micropapillary urothelial carcinoma (MPUC) is a rare and aggressive histological variant of urinary bladder cancer. A recent study published by Jin et al. in Cancer Medicine investigated the prognosis and survival rates of MPUC compared to conventional urothelial cancer (UC).

The authors included 154,972 patients registered in the national Surveillance, Epidemiology, and End Results (SEER) database from 2004 to 2016. Of those, 154453 patients were diagnosed with UC and 519 patients with MPUC. The authors found that MPUC patients had worse clinicopathological outcomes compared to UC patients. The study found that 63.39% of the MPUC group had a higher rate of muscle-invasive disease compared to 9.39% in the UC group (P < 0.001), 24.28% of the MPUC group had lymph node metastasis compared to 1.32% in the UC group (P < 0.001) and 10.79% of the MPUC group had lymph node metastasis compared to 1.17% in the UC group (P < 0.001). Patients with MPUC were more likely to have a radical cystectomy (P < 0.001), lymph nodes removal (P < 0.001), and pelvic exenteration (P < 0.001).

The risk of OM was significantly higher in the MPUC group compared to the UC group (HR = 1.39, 95% CI = 1.22-1.57, P < 0.0001). On the other hand, there was no significant difference in cancer-specific mortality (CSM) between the MPUC and UC groups (HR = 1.18, 95% CI = 1.00-1.40, P = 0.05).

This study confirms the aggressive nature of the micropapillary variant. Prospective trials of rare bladder cancer variants are ongoing to define the most effective treatment strategies.

Written by: Bishoy M. Faltas, MD, Director of Bladder Cancer Research, Englander Institute for Precision Medicine, Weill Cornell Medicine, New York City, New York

Reference:

  1. Jin D, Jin K, Qiu S, Zhou X, Yuan Q, Yang L, Wei Q. “Prognostic values of the clinicopathological characteristics and survival outcomes in micropapillary urothelial carcinoma of the bladder: A SEER database analysis.” Cancer Med. 2020 Jul;9(14):4897-4906. doi: 10.1002/cam4.3147. Epub 2020 Jun 11. PMID: 32529761
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