Comparative analysis of three vs. four cycles of neoadjuvant gemcitabine and cisplatin for muscle invasive bladder cancer.

PURPOSE: Because the optimal number of cycles of neoadjuvant gemcitabine and cisplatin chemotherapy (GC) is unclear, we aimed to compare disease response and survival outcomes of patients receiving either 3 or 4 cycles of neoadjuvant GC for muscle-invasive bladder cancer (MIBC). METHODS: A total of 166 patients who were treated with neoadjuvant GC and radical cystectomy for clinical stage T2-4N0M0 were identified. Response and effectiveness of different cycle counts were assessed using downstaging (complete pathologic and partial pathologic response), cancer-specific survival (CSS), and overall survival (OS). Response and survival outcomes were examined with adjusted logistic regression and Cox regression models. Statistical significance was defined as P < 0.05. RESULTS: Of 166 patients who received neoadjuvant GC, 107 (64.5%) received 3 cycles and 59 (35.5%) received 4 cycles. Age, insurance, comorbidity, tumor histology (pure urothelial carcinoma, urothelial with divergent differentiation, variant histology), and tumor stage were similar between the 2 treatment groups. Rates of complete response or any downstaging were similar between groups (21.5% and 40.2% in the 3-cycle group and 20.3% and 44.1% in the 4-cycle group, respectively). While disease response was similar (OR 1.03, 95% CI 0.43-2.45), both cancer-specific survival (HR 1.69, 95% CI 0.87-3.26) and overall survival (HR:1.88, 95% CI:1.02-3.48) were more favorable among patients managed with 4 cycles of neoadjuvant chemotherapy compared to those who received 3 cycles in adjusted models. CONCLUSIONS: Our analysis demonstrated that survival outcomes tended to be better among patients who received 4 cycle of neoadjuvant GC compared to those treated with 3 cycles. Although potential benefits of omission of fourth cycle may include expedited time to surgery, reduced chemotherapy-associated toxicity, and lower treatment costs, continuation of treatment with a fourth cycle of neoadjuvant GC chemotherapy may benefit patients with muscle-invasive bladder cancer and further improve disease outcomes.