ADT or MDT?

Top Line: What are the long-term outcomes of metastasis directed therapy (MDT) alone for oligometastatic, castration sensitive prostate cancer?

The Study: Two prospective, randomized phase 2 trials (STOMP and ORIOLE) have evaluated the concept of MDT alone versus observation for oligometastatic, metachronous castration sensitive prostate cancer (omCSPC). STOMP was a Belgian trial that enrolled 62 men with recurrence after primary treatment who were not on ADT and who had 3 or fewer metastases based on choline PET/CT and a controlled primary based on MRI and/or biopsy. MDT in STOMP included surgery (20%) or stereotactic body radiation (SBRT, 80%). ORIOLE was a multicenter US trial that enrolled 54 men with recurrence after primary therapy who were not on ADT and who had 3 or fewer mets based on CT, MRI, and/or bone scan (no PET scans). MDT in ORIOLE was SBRT/SABR. This pooled analysis takes a look at long-term outcomes and biomarker predictors of treatment outcome. Median progression-free survival (PFS, a composite endpoint including PSA and clinical events) was doubled with MDT compared to observation (12 versus 6 months), however there was no difference in radiographic PFS, time to castration resistance, or overall survival. A quarter of patients (24%) had high risk mutations (ATM, BRCA1/2, Rb1, TP53), which were associated with worse PFS than those without high risk mutations. In both groups, though, MDT resulted in improved PFS compared to observation.

TBL: A combined analysis of STOMP and ORIOLE shows improved PFS and durable disease control with MDT, though this approach still needs further refining as few patients with metastatic prostate cancer are observed in practice and as many as half may have additional occult metastases on PSMA PET. | Deek, J Clin Oncol 2022