Pathologic response in patients receiving neoadjuvant chemotherapy for muscle-invasive bladder cancer: Is therapeutic effect owing to chemotherapy or TURBT?

Overview

PURPOSE: We estimated the proportion of patients who received neoadjuvant chemotherapy for muscle-invasive bladder cancer whose tumors were downstaged by transurethral resection. MATERIALS AND METHODS: We identified patients with cT2 N0 urothelial carcinoma who underwent cystectomy at our institution from 2005 to 2014-overall, 139 underwent transurethral resection without chemotherapy, and 146 underwent transurethral resection with chemotherapy. Pathologic response was defined as2, P<0.01), lower prevalence of Charlson score≥3 (13.7% vs. 30.2%, P<0.01), and lower prevalence of prior non-muscle-invasive cancer (7.5% vs. 20.9%, P<0.01). More neoadjuvant patients achieved response compared with nonneoadjuvant patients (62.3% vs. 20.1%, RR = 3.10, P<0.01). Adjustment resulted in a RR of pathologic response in neoadjuvant vs. nonneoadjuvant patients of 2.60 (95% CI: 1.81-3.74, P<0.01). This adjusted RR indicates that among patients who receive neoadjuvant chemotherapy and undergo transurethral resection, 38% (95% CI: 27%-55%) of pathologic response can be attributed to transurethral resection. CONCLUSIONS: We estimate that in a cohort of patients who receive chemotherapy and undergo transurethral resection before cystectomy, 38% of pathologic response can be attributed to transurethral resection. Understanding who responds to chemotherapy and who responds to transurethral resection is needed to measure the effectiveness of both interventions.