A comparison of the survival outcomes of robotic-assisted radical prostatectomy and radiation therapy in patients over 75 years old with non-metastatic prostate cancer: A Korean multicenter study

PURPOSE: To compare overall survivals (OSs) and cancer-specific survivals (CSSs) after robotic-assisted radical prostatectomy (RARP) and radiation therapy (RT), the latter of which has long been recommended primarily for elderly patients (≥75 years) with non-metastatic prostate cancer (PCa), given the Korean male life span of 79.7 years (2018). MATERIALS AND METHODS: Retrospective data for aged ≥75 years who underwent RARP or RT at seven tertiary hospitals were analyzed. To account for indication-related bias, inverse probability of treatment-weighting (IPTW) was applied before and after Cox regression. RESULTS: Of the 1,110 study subjects, 883 underwent RARP and 227 RT from 2007 to 2016. The differences between groups including the age (≥80 y; 25.4% vs. 32.8%; p=0.034), concomitant diabetes (14.9% vs. 22.9%; p=0.007), coronary heart disease (3.5% vs. 7.5%; p=0.015), and PCa risk stratification (high-risk; 18.2% vs. 59.7%; p<0.001) were balanced after IPTW. During a mean follow-up of 74.5 months, OSs (91.9% vs. 91.0%) and CSSs (97.8% vs. 98.0%) were similar. After IPTW, overall mortality was associated with diabetes (hazard ratio [HR], 2.273; p<0.0001) and inversely with low-risk PCa (HR, 0.314; p<0.0001), the last of which was solely associated with cancer-specific mortality (HR, 0.245; p=0.0005). The implementation of local treatment between RARP and RT demonstrated no impact on survival, for whole and high-risk populations. CONCLUSIONS: Even aged over 75 years, patients who underwent RARP for non-metastatic PCa had similar survival with RT regardless of risk stratification. However, the survival needs to be weighed with the morbidity of local treatment in a future study.