Superior survival benefits of Radical Prostatectomy than External Beam Radiotherapy in aging 75 and older men with high-risk or very high-risk Prostate Cancer: a population-matched study

Objective: To evaluate the survival difference of radical prostatectomy (RP) and external beam radiotherapy (EBRT) in elderly men (75 years and older) with high-risk (HR) or very high-risk (VHR) prostate cancer (PCa). Methods: Elderly men diagnosed with HR/VHR PCa from 2004-2015 in the Surveillance, Epidemiology and End Results (SEER) database were identified. Propensity-score matching (PSM) was conducted to balance the covariates; Kaplan-Meier and Cox analysis were performed to evaluate the overall survival (OS) and prostate cancer-specific survival (PCSS). Results: 11698 patients with HR PCa and 4415 patients with VHR PCa were identified and divided into RP and EBRT group. After PSM, 964 patients with HR PCa and 538 patients with VHR PCa were included in each group. The 10-year OS and PCSS of men with HR PCa were 60.1% vs 40.9% and 90.6% vs 83.4%, respectively. The 10-year rate of OS and PCSS in men with VHR PCa were 55.9% vs 33.3% and 82.4% vs 75.6%, respectively. The OS curve of patients with HR PCa revealed that RP was significantly better than EBRT in both overall cohort [HR: 0.533, 95%CI (0.485~0.586), p<0.001] and the matched cohort [HR: 0.703, 95%CI (0.595~0.832), p<0.001]. However, the PCSS curve of patients with HR PCa showed that RP was significantly better than EBRT in overall cohort [HR: 0.453, 95%CI (0.368~0.559), p<0.001] but was similar to EBRT in matched cohort [HR: 0.820, 95%CI (0.552~1.218), p=0.327]. As for patients with VHR PCa, RP was associated with better OS than EBRT whether in overall cohort [HR: 0.520, 95%CI (0.457~0.592), p<0.001] or matched cohort [0.695, 95%CI (0.551~0.876), p=0.002]. The PCSS of RP was significantly better than that of EBRT in overall cohort [HR: 0.538, 95%CI (0.422~ 0.685), p<0.001], but was similar in matched cohort [HR: 0.787, 95%CI (0.510 ~1.214), p=0.281]. Conclusions: RP has more survival benefits than EBRT in men aged 75 years and older with HR or VHR PCa.