Does therapy of the primary tumor matter in oligometastatic prostate cancer? A prospective 10-year follow-up study.

The effect of curative treatment for oligometastatic prostate cancer patients is unsolved, both with regard to morbidity and mortality. With this study, we provide some of the first long-term follow-up data on progression and mortality in oligometastatic prostate cancer patients after curative treatment of their primary tumor. A cohort of 210 patients with diagnosed prostate cancer was established between 2008 and 2010. All patients were scheduled for intended curative treatment, and all underwent blinded F-choline positron-emission tomography/computed tomography at inclusion prior to curative treatment. Upon unblinding, 12 patients (6%) were recategorized as being oligometastatic. They had a mean age of 64 years, median prostate-specific antigen of 18 ng/mL, and median Gleason score of 7. Six patients were staged as T3, one T2, and five T1. The patients had a median of one bone metastasis (range 1-2). All underwent intended curative radiotherapy or prostatectomy. Mean follow-up was 10.1 (8.9-11.0) years. During follow-up of the 12 patients, three (25%) had biochemical recurrence, two developed castration-resistant disease, and one died due to prostate cancer. Our results suggest that intended curative treatment of the primary tumor in oligometastatic prostate cancer may have a role in highly selected patients.