A Phase II Study Evaluating Bone Marrow-Sparing, Image-guided Pelvic Intensity-Modulated Radiotherapy (IMRT) With Cesium-131 Brachytherapy Boost, Adjuvant Chemotherapy, and Long-Term Hormonal Ablation in Patients With High Risk, Nonmetastatic Prostate Cancer.

Abstract

Management of localized high-risk prostate cancer remains challenging. At our institution we performed a prospective phase II study of 2 years of androgen deprivation therapy (ADT), pelvic radiation, Cesium (Cs)-131 brachytherapy boost, and adjuvant docetaxel in high risk, localized prostate cancer with a primary endpoint of 3-year disease-free survival. Acute/chronic hematologic, gastrointestinal (GI) and genitourinary (GU) toxicities were scored based on the CTCAE v3.0/RTOG-EORTC criteria, respectively. Actuarial biochemical recurrence free survival (bRFS), bRFSdisease free survival (DFS) and overall survival (OS) were calculated. Patients had a median age of 62 years (range, 45 to 82), median Gleason score 8 (74% Gleason 8-10), median PSA of 11.2 (range, 2.8 to 96), and 47% cT2-T3a stage disease. Androgen deprivation was given for 2 years, 45 Gy whole-pelvis IMRT was followed by an 85 Gy Cs-131 boost to the prostate gland, and adjuvant docetaxel was given for 4 cycles. In total 38 patients enrolled from 2006 to 2014, with 82% completing protocol specified treatment, and 84.2% completing 4 cycles of docetaxel. Median follow-up for the entire and alive cohorts were 44 months and 58 months (range, 3.4 to 118), respectively. Acute grade ≥2 GI and GU toxicity rates were 18.4% and 23.7%, respectively. Chronic grade ≥2 GI and GU toxicity rates were 2.6% and 2.6%, respectively. Twelve patients (31.6%) developed grade 4 hematologic toxicity, with no grade 5 toxicity. The 5-year DFS, bRFS and OS rates were 74.1%, 86.0%, and 80.3%, respectively. This aggressive pilot multimodal approach appears to be safe and well-tolerated, providing disease control in a significant proportion of patients with particularly high-risk prostate cancer.