Surveillance or Metastasis-Directed Therapy for Oligometastatic Prostate Cancer Recurrence: A Prospective, Randomized, Multicenter Phase II Trial

Abstract

Purpose: Retrospective studies suggest that metastasis-directed therapy (MDT) for oligorecurrent prostate cancer (PCa) improves progression-free survival. We aimed to assess the benefit of MDT in a randomized phase II trial. Patients and Methods: In this multicenter, randomized, phase II study, patients with asymptomatic PCa were eligible if they had had a biochemical recurrence after primary PCa treatment with curative intent, three or fewer extracranial metastatic lesions on choline positron emission tomography-computed tomography, and serum testosterone levels > 50 ng/mL. Patients were randomly assigned (1:1) to either surveillance or MDT of all detected lesions (surgery or stereotactic body radiotherapy). Surveillance was performed with prostate-specific antigen (PSA) follow-up every 3 months, with repeated imaging at PSA progression or clinical suspicion for progression. Random assignment was balanced dynamically on the basis of two factors: PSA doubling time (≤ 3 v > 3 months) and nodal versus non-nodal metastases. The primary end point was androgen deprivation therapy (ADT)-free survival. ADT was started at symptomatic progression, progression to more than three metastases, or local progression of known metastases. Results: Between August 2012 and August 2015, 62 patients were enrolled. At a median follow-up time of 3 years (interquartile range, 2.3-3.75 years), the median ADT-free survival was 13 months (80% CI, 12 to 17 months) for the surveillance group and 21 months (80% CI, 14 to 29 months) for the MDT group (hazard ratio, 0.60 [80% CI, 0.40 to 0.90]; log-rank P = .11). Quality of life was similar between arms at baseline and remained comparable at 3-month and 1-year follow-up. Six patients developed grade 1 toxicity in the MDT arm. No grade 2 to 5 toxicity was observed. Conclusion: ADT-free survival was longer with MDT than with surveillance alone for oligorecurrent PCa, suggesting that MDT should be explored further in phase III trials. Trial registration: ClinicalTrials.gov NCT01558427.