Achieving PSA < 0.2 ng/ml before Radiation Therapy Is a Strong Predictor of Treatment Success in Patients with High-Risk Locally Advanced Prostate Cancer

Abstract

Background. To predict long-term treatment outcome of radiation therapy (RT) plus androgen deprivation therapy (ADT) for high-risk locally advanced prostate cancer. Methods. In total, 204 patients with the National Comprehensive Cancer Network (NCCN) high risk locally advanced prostate cancer (PSA > 20 ng/ml, Gleason score ≧ 8, clinical T stage ≧ 3a) were treated with definitive RT with ADT. Median follow up period was 113 months (IQR: 95-128). Median neoadjuvant ADT and total ADT duration were 7 months (IQR: 6-10) and 27 months (IQR: 14-38), respectively. Results. PSA recurrence-free survival (PSA-RFS), cancer specific survival (CSS), and overall survival (OS) rates at 5 years were 84.1%, 98.5%, and 93.6%, respectively, and 67.9%, 91.2%, and 78.1%, respectively, at 10 years. Pre-RT PSA less than 0.2 ng/ml was associated with superior outcomes of PSA-RFS (HR = 0.42, 95% CI: 0.25-0.70, p=0.001), CSS (HR = 0.27, 95% CI: 0.09-0.82, p=0.013), and OS (HR = 0.48, 95% CI: 0.26-0.91, p=0.021). On multivariate analysis, age (≥70 y.o.) and pre-RT PSA (≥0.2 ng/ml) were factors predictive of poorer OS (p=0.032), but iPSA, T stage, Gleason score, number of NCCN high-risk criteria, a combination with anti-androgen therapy and neoadjuvant ADT duration were not predictive of treatment outcome. Conclusion. In patient with high-risk prostate cancer, RT plus ADT achieved good oncologic outcomes. PSA < 0.2 ng/ml before radiation therapy is a strong independent predictor for long overall survival.