Trimodality Therapy With or Without Neoadjuvant Chemotherapy for Muscle-Invasive Bladder Cancer

Background: Bladder-sparing chemoradiation therapy is a definitive first-line treatment option for muscle-invasive bladder cancer. Randomized trials have demonstrated that the addition of neoadjuvant chemotherapy to radical cystectomy or radiation monotherapy results in a survival benefit. Whether neoadjuvant chemotherapy improves outcomes when used with definitive chemoradiation is unknown.

Patients and methods: We identified 2566 patients in the National Cancer Data Base with cT2-4N0M0 urothelial cell carcinoma of the bladder treated with definitive intent concurrent chemoradiation from 2004 to 2015. The exposure of interest was receipt of neoadjuvant chemotherapy versus those without neoadjuvant chemotherapy. The primary outcome was overall survival defined from the time of diagnosis. Kaplan-Meier and multivariable Cox proportional hazard analyses were used to compare survival between groups. Sensitivity analyses tested (1) an interaction term for clinical T stage and (2) defining survival from start of radiation (as opposed to time of diagnosis) to address potential leading time bias.

Results: We identified 462 patients treated with neoadjuvant chemotherapy followed by chemoradiation and 2104 patients treated with chemoradiation alone. With a median follow-up of 6.2 years, we found no difference in survival between groups: 5-year or 10-year overall survival of 30.6% (95% confidence interval [CI], 28.4%-32.9%) in the neoadjuvant group versus 31.8% (95% CI, 27.0%-36.8%) in the standard chemoradiation therapy group and 13.3% (95% CI, 11.2%-15.5%) in the neoadjuvant group versus 13.0% (95% CI, 8.4%-18.7%) in the standard chemoradiation therapy group, respectively (log-rank P = .19). On multivariable analysis we found no association between receipt of neoadjuvant chemotherapy and overall survival (hazard ratio, 1.01; 95% CI, 0.88-1.15; P = .921). The sensitivity analyses did not identify any differential effect by clinical T stage nor by defining survival from start of radiation.

Conclusion: These results do not support the routine addition of neoadjuvant chemotherapy to definitive chemoradiation for bladder cancer, and optimizing the chemotherapy sequencing and regimens for bladder-preserving approaches to muscle invasive bladder cancer should continue to be studied under prospective clinical trials.