Salvage ablative therapy in prostate cancer: international multidisciplinary consensus on trial design.

INTRODUCTION: Salvage ablative therapy (SAT) has been developed as a form of localized treatment for localized recurrence of prostate cancers following radiation therapy. To better address the utility of SAT, prospective clinical trials must address the aspects of accepted standards in the initial evaluation, treatment, follow-up, and outcomes in the oncology community. We undertook this study to achieve consensus on uniform standardized trial design for SAT trials.
METHODS: A literature search was performed and an international multidisciplinary group of experts was identified. A questionnaire was constructed and sent out to 71 participants in 3 consecutive rounds according to the Delphi method. The project was concluded with a face-to-face meeting in which the results were reviewed and conclusions were formulated.
RESULTS: Patients with recurrent disease after radiation therapy were considered candidates for a SAT trial using any ablation scenario performed with cryotherapy or high-intensity focused ultrasound. It is feasible to compare different sources of energy or to compare with historical data on salvage radical prostatectomy outcomes. The primary objective should be to assess the efficacy of the treatment for negative biopsy rate at 12 months. Secondary objectives should include safety parameters and quality-of-life assessment. Exclusion criteria should include evidence of local or distant metastases. The optimal biopsy strategy is image-guided targeted biopsies. Follow-up includes multiparametric magnetic resonance imaging, prostate-specific antigen level, and quality of life for at least 5 years.
CONCLUSIONS: A multidisciplinary board from international experts reached consensus on trial design for SAT in prostate cancer and provides a standard for designing a feasible SAT trial.