A Nationwide Persistent Underutilization of Adjuvant Radiotherapy in North American Prostate Cancer Patients

Objective To examine the utilization of adjuvant radiotherapy (aRT) in contemporary prostate cancer patients with adverse pathological features at radical prostatectomy (RP). Methods We identified 189,240 patients with adverse features at RP (positive margin, stage ≥pT3a, and/or pN1 disease), from 2004 to 2015, within the National Cancer Database, and validated our findings within Surveillance, Epidemiology, and End Results (SEER) program. We examined the utilization of patients with aRT with adverse features at RP and patients with very aggressive disease (at least 2 of the following: ≥pT3b, pathological Gleason 8-10, and pN1). Regression analysis examined the relationship of various predictors of utilization adjusting to confounders. Pseudo R2 analysis examined the magnitude of influence that each variable had on the decision to use aRT. Results Within the National Cancer Database cohort, only 11.7% of our patients received aRT. In patients with very aggressive disease, aRT utilization rate was 28.9%. Within the SEER cohort, 16.3% of patients with any adverse features at time of RP received aRT. In patients with very aggressive disease, only 30% of patients received aRT. Further, year of diagnosis, Gleason grade, pathologic stage, and positive surgical margin were the variables that had the greatest influence on the decision to use aRT, and that positive surgical margin, type of institution at which care was received, and lymph node involvement were the most influential variables in patients with very aggressive disease. Conclusions The current standard of care in the United States represents a significant underutilization of aRT in eligible patients with prostate cancer. Urgent efforts are necessary to address this quality-of-care concern.