Micropapillary bladder cancer: a clinico-pathological characterization and treatment analysis

Abstract

Purpose: Micropapillary bladder cancer (MPBC) is a very rare and aggressive variant of urothelial carcinoma (UC). The aim of this study was to investigate the clinico-pathological characteristics, treatment, and prognosis of MPBC to improve the understanding of this invasive disease. Methods: We reviewed the records of 6 patients with MPBC who were evaluated and treated at our hospital between 2009 and 2015, and additionally reviewed 38 cases reported in the literature. Results: In 44 cases, 36 cases (81.8%) were male and 8 cases (18.2%) were female, with a male:female ratio of 4.5:1; the median age of the patients was 68 years (range 45–91 years). A majority (81.8%) of patients with cT1 above or with lymph node and distant metastasis (cT2N0 in 18.2%, cT3-4N0 in 13.6%, cTanyN+ in 43.2%, and cTanyM+ in 6.8%). There was a high grade in 70.5% of patients. Lymphovascular invasion (LVI) was present in 61.4% of patients, and LVI in cT2 was more common than in cT1 (71.4 vs 22.2%). 52.3% of patients were treated with radical cystectomy (RC). After a mean follow-up of 16.2 months, 77.3% of patients developed distant metastases, and 47.7% of patients died of the disease. The mean overall survival (OS) was 28.9 months and the median OS was 20 months, and the amount of micropapillary (MPP) is correlated inversely with prognosis. Conclusions: Micropapillary bladder cancer is a rare variant of UC associated with a poor prognosis, which often presents at an advanced stage with LVI and distant metastases. The optimal treatment strategy is early RC combined with chemotherapy.