D. LaBella1, C. C. Huang2, and R. E. Fecteau3; 1Department of Radiation Oncology, Duke University Medical Center, Durham, NC, 2Duke University Medical Center, Durham, NC, 3NewYork-Presbyterian/Weill Cornell Medical Center, New York, NY
Purpose/Objective(s): Approximately 10% of patients diagnosed with prostate cancer have evidence of metastasis at the time of presentation.Historically, management was restricted to systemic therapy. STAMPEDE arm H demonstrated that progression free survival and overall survival improved in patients with low volume metastatic disease if the prostate was treated with radiotherapy. Recently, small phase II studies have evaluated the role of metastasis directed therapy (MDT) in patients with de novo oligometastatic disease. The purpose of this study was to evaluate the effectiveness of oligometastasis-directed stereotactic body radiation therapy (OMD-SBRT) therapy for patients with de novo oligometastatic prostate cancer.Materials/
Methods: This single institution retrospective reviewevaluatedpatientsdiagnosed with de novolow burdenoligometastatic (<6 bone or nodal metastases)prostate cancer. All patients underwentOMD-SBRTtoall known bone or nodal oligometastases.Overall survival, biochemical-progression free survival (bPFS), freedom from local failure,and freedom from distant failure rates from time of diagnosis were computed using Kaplan-Meier estimators. Lesion-wise time to local failure was recorded. Results: A total of 30 patients that underwent OMD-SBRT to a total of 56 lesions were evaluated. The median follow-up was 48 months. Two, 7, 6, 13, and 2 patients had total Gleason scores of 6, 7, 8, 9, and 10, respectively. Twenty-six patients underwent prostate directed radiotherapy, 3 patients underwent radical prostatectomy, and one patient did not have prostate directed therapy. Fifty-four osseous lesions and 2 pelvic nodes were treated with OMD-SBRT. SBRT prescription doses ranged from 18-50Gy in 1-5 daily fractions. Median prescription target volume was 44.65cc. Five-year overall survival estimate was 88.2% (95% CI, 60.6% to 96.2%), bPFS estimate was 73.7% (95% CI, 47.9% to 88.1%), freedom from local failure estimate was 93.8% (95% CI, 63.2% to 99.1%), and freedom from distant failure estimate was 87.5% (95% CI, 58.6% to 96.7%). Four of 56 treated lesions had evidence of local failure and time to lesion local failure was 12, 20, 20, and 32 months. Conclusion: Our findings suggest that OMD-SBRT may offerbenefits in delaying local and distant recurrences in patients with de novo oligometastatic prostate cancer.The implications for future research should compare OMD-SBRT to conventional management strategies in patients with de novo oligometastatic prostate cancer.
