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): Recent retrospective and phase II randomized studies have evaluated the role of metastasis directed therapy for oligorecurrent prostate cancer, with a focus on androgen deprivation therapy free survival and radiation associated toxicity. This study evaluated the effectiveness of oligorecurrence-directed stereotactic body radiation therapy (ORD-SBRT) therapy for patients with oligorecurrent prostate cancer.Materials/
Methods: This single institution retrospective review evaluatedpatients with oligorecurrent prostate cancer that were treated with ORD-SBRT to all known osseous and nodal oligometastasis between 2016-2024. Patients were allowed to have had prior radiotherapy to the prostate or other sites.Patients with other non-skin cancer diagnosis were excluded.Patient survival status and systemic/hormonal therapy status at time of last follow-up was recorded.Lesion-wise time to local failure (TTLF) was recorded. Results: A total of 49 patients that underwent ORD-SBRT to a total of 65 lesions were evaluated. A total of 12 recurrent radiotherapy targets were treated with non-SBRT techniques, and they were not included in lesion wise analysis.Forty-nine patients were diagnosed with oligorecurrent prostate cancer after primary treatment with radical prostatectomy (n=38) or definitive radiotherapy (n=11). A total of 41 (83.7%) patients received hormonal and/or systemic therapy. The median follow-up was 116 months from time of diagnosis, and 16 months from completion of the most recent ORD-SBRT course.Four, 15, 17, 10, and 0 patients with evaluable pathology had total Gleason scores of 6, 7, 8, 9, and 10, respectively. 61 osseous lesions, 6 abdominopelvic nodes, 1 hilar node, and 1 set of bilateral adrenal glands were treated with ORD-SBRT. SBRT prescription doses ranged from 17-50Gy in 1-5 daily fractions, with the exception of one patient who received 8Gy in 1 fraction. Median prescription target volume was 42.29cc. At median follow-up, 14 patients (28.6%) were alive with no evidence of disease and off systemic/hormonal therapy, 17 patients (34.7%) were alive with no evidence of disease while on systemic/hormonal therapy, 14 patients (28.6%) were alive with progressive disease on systemic/hormonal therapy, 3 patients (6.1%) died of metastatic prostate cancer, and 1 patient (2.0%) died of other causes. Three patients (6.1%) had local failure of an ORD-SBRT treated lesion, all osseous, with TTLF of 6, 17, and 23 months. Conclusion: Our findings suggest that ORD-SBRT has high local control rates, and it may offer benefitin reducingandrogen deprivation or systemic therapy usage after ORD-SBRT for patients with oligorecurrentprostate cancer. Future randomized control trials should continue to investigate the role of ORD-SBRT compared to surveillance or systemic therapy alone for oligorecurrent prostate cancer.
