Metastasis-directed Therapy Without Androgen Deprivation Therapy in Solitary Oligorecurrent Prostate Cancer

As controversy remains regarding the role of metastasis-directed therapy in patients with oligometastatic prostate cancer, we sought to characterize outcomes of metastasis-directed therapy without concomitant androgen deprivation therapy in the specific subset of patients with a solitary metastatic lesion on C-11 choline positron emission tomography imaging whose primary tumor has already been treated.We identified 124 consecutive prostate cancer patients from 2008 to 2018 with a solitary oligorecurrent metastatic lesion on positron emission tomography imaging who were treated with metastasis-directed therapy without androgen deprivation therapy from the Mayo Clinic C-11 choline registry. Metastasis-directed therapy consisted of either stereotactic body radiation therapy or surgical excision.Of these 124 patients, 67 were treated with surgery (median follow-up 54 months) and 57 patients were treated with stereotactic body radiation therapy (median follow-up 53 months). Of patients treated with surgery, 80.5% had >50% decline in prostate specific antigen at first follow-up, and the 3-year radiographic progression-free survival was 29%. Median time to initiation of systemic therapy in this cohort was 18.5 months (interquartile range 8.4-44.7 months). Meanwhile, for patients treated with stereotactic body radiation therapy, 40.3% had >50% decline in prostate specific antigen at first follow-up, and the 3-year radiographic progression-free survival was 17%. Similarly, median time to initiation of systemic therapy was 17.8 months (interquartile range 7.1-42.3 months).This study represents the first reported series of metastasis-directed therapy without androgen deprivation therapy in patients with solitary oligorecurrent metastatic prostate cancer. These results suggest that metastasis-directed therapy without androgen deprivation therapy can delay initiation of systemic therapy and highlight the need for further prospective study for select patients with solitary metastatic recurrences of prostate cancer.