Is neoadjuvant chemotherapy beneficial before radical cystectomy? Examining the external validity of the SWOG-8710 trial.

Abstract

331 Background: The use of neoadjuvant chemotherapy (NAC) before radical cystectomy (RC) is supported by results from several randomized control trials, including SWOG-8710. We sought to test the applicability of the SWOG-8710 study in the general population. Methods: We used the National Cancer Data Base (NCDB) to identify patients with non-metastatic muscle-invasive urothelial carcinoma of the bladder who underwent RC between 2004 and 2012. The primary endpoint was overall survival (OS). Secondary endpoints were rates of downstaging (pT0), positive pathologic lymph nodes (pN+), margin status, postoperative readmission, length of hospital stay (LOS), and 30 and 90-day postoperative mortality rates. OS comparison using Cox regression analysis was conducted. Furthermore, logistic regression models examining secondary outcomes were fitted. To adjust for potential selection bias, propensity score weighted analyses were performed. Results: Of 8732 patients who underwent RC, 1619 (19%) received NAC. Compared to the SWOG-8710 cohort, our population was older, more commonly female (p=0.002), and had higher clinical stage (p<0.001). Following propensity score adjustment, receipt of NAC was associated with an OS benefit (Hazard Ratio [HR]: 0.88, p=0.017). On secondary outcome analysis, higher downstaging rates (Odds Ratio [OR]: 5.03, p<0.001) and lower 30-day (OR: 0.49, p=0.019) and 90-day (OR: 0.61, p=0.009) postoperative mortality rates were recorded in patients who received NAC. Conclusions: Despite baseline differences between patients from the SWOG-8710 trial and general urologic practice, NAC is associated with an OS advantage relative to RC alone. Continued efforts should focus on promoting the use of NAC in appropriate patients.