The Ability of the STAR-CAP Staging System to Prognosticate the Risk of Subsequent Therapies and Metastases After Initial Treatment of M0 Prostate Cancer

Introduction The International Staging Collaboration for Prostate Cancer (STAR-CAP) has been proposed as a risk model for prostate cancer with superior prognostic power compared to the current staging system. This study aimed to evaluate the performance of STAR-CAP in predicting the risk of subsequent therapy after initial treatment and the risk of developing metastases. Patients and Methods The study included 3425 men from an institutional observational registry with a median age of 64.9 years and a median follow-up time of 5.4 years. The primary endpoints were metastases and progression to additional therapy after initial therapy (radiation ± surgery). The risk of progression in the STAR-CAP group was estimated using a competing risk model (death). Results The results showed that patients with STAR-CAP stages 1A-1C had a similar risk of requiring additional therapies and developing metastasis. Compared to stage IC, each stage from 2A to 3B incrementally increased the risk of subsequent therapy (hazard ratio (HR) 1.4 to 5.8, respectively) and metastases (HR 1.5 to 10.8, respectively). The 5-year probability of receiving subsequent therapy for a patient with stage IC was 8.6%, which increased from 11.4% to 37.4% for those with stages 2A to 3B. The 5-year probability of developing metastases for patients with stage IC was 1.5%, which increased from 2.2% to 8.2% for patients with stages 2A to 3B. Conclusions The probability of receiving subsequent therapy was higher for patients undergoing surgery, while radiation therapy patients were more likely to receive treatment with intensified multimodality therapies upfront. Micro Abstract A study of 3425 men showed that those with STAR-CAP stages 1A-1C had similar risk of needing additional therapies and developing metastases after primary treatment. Stages 2A to 3B increased the risk of these outcomes. Men who underwent surgery were more likely to receive subsequent therapy, while radiation therapy patients were more likely to receive upfront intensified multimodality therapies.