Pathological response to neoadjuvant chemotherapy for muscle-invasive micropapillary bladder cancer

What's known on the subject? and What does the study add? Micropapillary bladder cancer is a high grade variant with poor prognosis. There is no consensus about patients with micropapillary bladder cancer receiving neoadjuvant chemotherapy, but many suggest that radical cystectomy should not be delayed. Data from this study suggest that patients with micropapillary bladder cancer have a similar rate of response to neoadjuvant chemotherapy to that of patients with urothelial carcinoma. If these patients have pT0 disease, their survival is significantly improved at 2 years. Objective To describe the pathological outcomes of patients with muscle-invasive micropapillary bladder cancer who have undergone neoadjuvant chemotherapy. Patients and Methods A total of 82 patients with muscle-invasive micropapillary bladder cancer were treated between 1997 and 2010. After excluding those with metastatic disease, micropapillary histology only at radical cystectomy (RC), and chemo-radiation as primary treatment, 44 patients remained. All patients had cT2 disease before chemotherapy/surgery. The median follow-up after RC was 28 months. Neoadjuvant chemotherapy was initiated in 29 (66%) patients and all patients underwent RC (93%) or partial cystectomy (7%). Results Micropapillary histology was diagnosed at first transurethral resection in 37 (84%) patients. Final RC pathology revealed pT0 in 15 (34%) patients and positive lymph nodes in 13 (31%) patients. Down-staging to pT0 occurred in 13 (45%) of those who received neoadjuvant chemotherapy compared with two (13%) of those who did not (P = 0.049). Patients with pT0 disease with micropapillary histology had higher overall survival rates (25 vs. 92%) and lower rates of bladder cancer recurrence (21 vs. 79%) at the 24-month follow-up. Conclusions Almost half of the patients responded completely to neoadjuvant chemotherapy with a pT0 rate of 45%; therefore, patients with the micropapillary variant of urothelial carcinoma should not be excluded from consideration for neoadjuvant chemotherapy.