Neoadjuvant chemotherapy in the treatment of muscle invasive bladder cancer with mixed histology.

Introduction: We examined the effects of neoadjuvant chemotherapy (NC) in the treatment of muscle invasive urothelial carcinoma of the bladder in those with mixed histology (MH) versus those with pure urothelial carcinoma (UC).

Materials And Methods: Between 2000-2012, 195 patients were identified with clinical stage T2-T4, N0-Nx, M0-Mx UCB who had either NC (+/- radical cystectomy) (n = 63) or radical cystectomy (RC) alone (n = 132). Tumors were classified as either pure UC or MH. Endpoints included downstaging to pT0 and overall survival. Multivariable Cox regression and the Kaplan-Meier method were used to estimate the effects of histological type and treatment given on overall mortality.

Results: The rate of downstaging to pT0 was higher in NC treated patients with both MH (p = 0.048) and pure UC (p < 0.0001), as compared to those in each group who did not receive NC. NC was not a significant predictor of overall survival for MH patients in a Cox multivariate model (p = 0.54). However, among all patients treated with NC, MH was found to be a predictor of poorer survival compared to UC (p = 0.02).

Conclusions: Prior evidence on the benefits of NC for patients with MH is mixed, but our data suggests that there is improvement in rate of pT0 on final pathology in those treated with NC, regardless of histology. Although patients with MH fare worse than those with pure UC in the setting of NC, given the significantly higher rate of pT0 at final pathology, strong consideration should be given to use of NC in the treatment of MH muscle invasive bladder cancer patients.