Objective : Over 80% of patients with metastatic prostate cancer develop bone metastases, a finding that is associated with increased morbidity and mortality. While the standard of care approach to metastatic prostate cancer is systemic treatment with androgen-deprivation therapy, there is growing evidence that cytoreductive interventions can improve outcomes. Osseous prostate cancer metastases, however, represent a treatment challenge given their sclerotic composition and radioresistance. The purpose of this study was to evaluate the efficacy of cryoablation on local control of osseous prostate cancer metastases.
Methods : A single institution, IRB-approved retrospective review of patients with prostate cancer with osseous metastases who underwent cryoablation was performed. Local progression free survival was determined by evaluating for recurrent malignancy at the site of cryoablation based on functional imaging studies (MDP bone scan, C-11 methionine PET/CT, or F-18 fluciclovine PET/CT). Interval change in prostate serum antigen (PSA) levels was also analyzed.
Results : A total of 24 patients were included in this study. The median age was 69, and the median Gleason score was 8. The majority of patients (79%) underwent cryoablation in the setting of oligometastatic disease. Most patients (71%) had developed castration resistance prior to cryoablation. Osseous metastases in the pelvis were the most common site for cryoablation followed by rib lesions. There were no major procedural complications. Local tumor control was maintained throughout the study period in 83% of patients with a median follow up time of 6.1 months. Estimated local progression free survival rates at 6 and 12 months were 82% and 75%, respectively. Serum PSA levels at 3 months following cryoablation were decreased compared to baseline in 55% of patients; for 35% of patients, this decrease was at least 40% or more compared to baseline.
Conclusions : Cryoablation is an effective treatment option for achieving local control of prostate cancer osseous metastases.