Dr Jia on the Evolving Role of Metastasis-Directed Radiotherapy in Prostate Cancer

Angela Jia, MD, PhD, a radiation oncologist at University Hospitals, as well as an assistant professor of medicine at Case Western Reserve University School of Medicine, discusses the current standing of metastasis-directed radiotherapy in prostate cancer and identifies some lingering questions surrounding the modality.

Currently available data from clinical trials have shown that metastasis-directed radiotherapy is feasible and well tolerated in prostate cancer, Jia begins. Randomized clinical studies such as the ORIOLE (NCT02680587) and other phase 2 (NCT01558427) trials have demonstrated that metastasis-directed approaches including stereotactic ablative radiation (SABR) offer a significant benefit compared with standard-of-care approaches for the treatment of patients with oligometastatic prostate cancer.

Findings from ORIOLE showed that patients who received SABR (n = 36) achieved a median progression-free survival (PFS) that was not reached (NR) vs 5.8 months for patients undergoing observation (n = 18; HR, 0.30; 95% CI, 0.11-0.81; P = .002). Additionally, the median biochemical PFS was NR vs 6.4 months, respectively (HR, 0.31; 95% CI, 0.13-0.75; P = .002). In the other phase 2 study, patients treated with metastasis-directed therapy with either stereotactic body radiotherapy (SBRT) or surgery (n = 31) experienced a median androgen deprivation–therapy-free survival of 21 months (80% CI, 14-29) compared with 13 months (80% CI, 12-17) for patients who underwent surveillance (n = 31; HR, 0.60; 80% CI, 0.40-0.90; log-rank P = .11).

However unanswered questions remain regarding the approach, including sequencing considerations and the role of metastasis-directed radiotherapy in combination regimens, Jia explains. These questions are currently being investigated in clinical trials and the answers will hopefully be forthcoming, Jia notes. The ideal timing of when to use metastasis-directed radiotherapy is also being further elucidated, Jia says. Investigators are working to identify predictive biomarkers to better determine which patients will benefit most from metastasis-directed radiotherapy, Jia concludes.