National Practice Patterns and Overall Survival After Adjuvant Radiotherapy Following Radical Cystectomy for Urothelial Bladder Cancer in the USA, 2004-2013

Background: Adjuvant radiation therapy (ART) after radical cystectomy (RC) for urothelial bladder cancer (UBC) may play a role in the management of muscle-invasive BC, particularly in patients with locally advanced disease and adverse pathologic features (pT3/4 or positive surgical margins [PSMs]). Evidence regarding the effect of ART on overall survival (OS) is lacking.

Objective: To evaluate national practice patterns for the use of ART and assess its impact on OS for patients with adverse pathologic features (APF) after RC.

Design, setting, and participants: Using the National Cancer Data Base, we analyzed all UBC cases with APF after RC from 2004 to 2013. Patients were divided into ART and no-ART groups.

Outcome measurements and statistical analysis: Relationships with oncological outcomes were analyzed using multivariable Cox regression and log-rank analyses.

Results and limitations: Use of ART decreased during the study period from 3.1% in 2004 to 1.7% in 2013 (p=0.03). ART was administered in 1.4%, 4.0% and 5.2% of patients with pT3 UBC, pT4 UBC, and PSMs (any pT stage), respectively. The rate of ART was significantly higher among younger ages, female sex, low-volume hospitals, nonacademic community care centers, higher stages, PSMs, perioperative chemotherapy, and lymph node-positive disease. Predictors of ART receipt were PSMs (odds ratio [OR] 3.4; p<0.0001), pT4 (OR 2.6; p=0.02), community based centers (OR 2.1; p<0.0001), and female sex (OR 1.8; p<0.0001). Risk factors for worse OS included age, higher tumor stage and comorbidities, PSMs, positive nodes, and suboptimal lymph node dissection (<10 nodes removed; all p<0.001). ART was not independently associated with better OS in the full cohort (p=0.54). However, subgroup analyses suggested an OS benefit for patients with PSMs (hazard ratio 0.73; p=0.047). Limitations include the retrospective design and limited details regarding cancer-specific survival.

Conclusions: Use of ART for APF following RC is not common in the USA and the rate of ART has been decreasing over time. ART may have an OS benefit after RC for patients with PSMs.

Patient summary: In this report we looked at the outcomes for patients with locally advanced bladder cancer receiving adjuvant radiation therapy following cystectomy in a large US population. We found that adding radiation therapy after removing the bladder cancer may have some survival benefits for patients with positive surgical margins.