Comparative Survival Outcomes of High-risk Prostate Cancer Treated with Radical Prostatectomy or Definitive Radiotherapy Regimens

BACKGROUND: Observational data has indicated improved survival after radical prostatectomy (RP) compared with definitive radiotherapy (RT) in men with high-risk prostate cancer (PCa). OBJECTIVE: To compare PCa-specific mortality (PCSM) and overall mortality (OM) in men with high-risk PCa treated with RP or RT, providing information on target doses and fractionations. DESIGN, SETTING, AND PARTICIPANTS: This is an observational study from the Cancer Registry of Norway. Patients were diagnosed with high-risk PCa during 2006–2015, treated with RP ≤12 mo or RT ≤15 mo after diagnosis, and stratified according to RP or RT modality; external beam radiotherapy (EBRT; 70–<74, 74–<78, or 78 Gy), hypofractionated RT or EBRT combined with brachytherapy (BT-RT). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Competing risk and Kaplan-Meier methods estimated PCSM and OM, respectively. Multivariable Cox regression models evaluated hazard ratios (HRs) for PCSM and OM. RESULTS AND LIMITATIONS: In total, 9254 patients were included (RP 47%, RT 53%). RT patients were older, had poorer performance status and more unfavorable disease characteristics. With a median follow-up time of seven and eight yrs, the overall 10-yr PCSM was 7.2% (95% confidence interval [CI] 6.4–8.0) and OM was 22.9% (95% CI 21.8–24.1). Compared with RP, EBRT 70–<74 Gy was associated with increased (HR 1.88, 95% CI 1.33–2.65, p < 0.001) and BT-RT with decreased (HR 0.49, 95% CI 0.24–0.96, p = 0.039) 10-yr PCSM. Patients treated with EBRT 70–78 Gy had higher adjusted 10-yr OM than those treated with RP. CONCLUSIONS: In men with high-risk PCa, treatment with EBRT <74 Gy was associated with increased adjusted 10-yr PCSM and OM, and BT-RT with decreased 10-yr PCSM, compared with RP. PATIENT SUMMARY: In this study, we compared mortality after radical prostatectomy (RP) and radiotherapy (RT) in men with high-risk prostate cancer (PCa); the results suggest that men receiving lower-dose RT have higher, and patients receiving brachytherapy may have lower, risk of death from PCa than patients treated with prostatectomy.