PSOR3 Presentation Time: 11:40 AM: The Role of CAPRA Score as a Predictor of Outcomes in High-Risk Prostate Cancer Patients Treated with EBRT Plus HDR Brachytherapy Boost: A 20-year Single-Institution Experience

Abstract

<h3>Purpose</h3> The study aimed to report clinical outcomes of high-risk prostate cancer (PCa) patients treated with external beam radiation therapy (EBRT) and high dose-rate boost (HDRB) according to CAPRA score. <h3>Material and Methods</h3> The study sample consisted of 361 high-risk PCa patients stratified according to D'Amico classification and treated with EBRT and HDRB and antiandrogen therapy (ADT) between 1999 and 2016. We conducted retrospective competing-risk survival analyses to compare individuals with a CAPRA score lesser than or equal to five and greater than five on biochemical recurrence (BCR) and metastasis incidence. Kaplan-Meier analysis was performed to assess overall survival (OS). Subsequently, we used ROC curves to compare the performance of the CAPRA model to the MSKCC stratification tool on BCR and metastasis incidence. <h3>Results</h3> The mean age of the patients at treatment time was 69.6±7.3 years. The median follow-up was 55.5 months. Of the 361 individuals, 52,4 % (n=189) had a CAPRA score above five. In comparison to individuals with a CAPRA score lesser than or equal to five, individuals with a CAPRA score above five were deemed at higher risk of BCR (sHR = 2.74, 95% CI: 1.12-6.66, p=0.027) and demonstrated a tendency towards significance in their metastasis incidence trend (sHR 2.33 95% CI: 0.89-6.12, p = 0.085). For 10-year OS, there was a HR for mortality of 1.89 (95% CI: 1.04-3.43, p=0.036) for individuals with a CAPRA score above five. There was no significant difference between either risk stratification strategy in ROC curves analysis. <h3>Conclusions</h3> The data suggest that patients' tumours classified as high-risk using the CAPRA score correlated with a higher risk of BCR, metastasis, and mortality when compared to lower-risk tumours. Further studies are needed to validate the use of the CAPRA score to predict cancer-specific mortality (CSM) as an initial risk stratification tool.