In a Belgian phase II study reported in the Journal of Clinical Oncology, Ost et al found that androgen deprivation therapy (ADT)-free survival was prolonged with metastasis-directed therapy vs surveillance in recurrent oligometastatic prostate cancer.
Sixty-two patients with asymptomatic disease were randomly assigned to metastasis-directed therapy of all detected lesions with surgery or stereotactic body radiotherapy (n = 31) or surveillance (n = 31). Surveillance consisted of prostate-specific antigen (PSA) follow-up every 3 months, with repeated imaging at PSA progression or clinically suspected progression. Patients had to have biochemical recurrence after primary treatment with curative intent, ≤ 3 extracranial metastatic lesions on choline positron-emission tomography–computed tomography, and serum testosterone levels > 50 ng/mL. The primary endpoint was ADT-free survival; ADT was started at symptomatic progression, progression to > 3 metastases, or local progression of known metastases.
Median follow-up was 3 years. Metastasis-directed therapy consisted of stereotactic body radiotherapy in 25 patients and surgery in 6.
On intent-to-treat analysis, median ADT-free survival was 21 months (80% confidence interval [CI] = 14–29 months) in the metastasis-directed therapy group vs 13 months (80% CI = 12–17 months) in the surveillance group (hazard ratio = 0.60, 80% CI = 0.40–0.90, P = .11). The primary reason for initiating ADT was polymetastatic progression in both groups. No symptomatic or local progression was observed in the metastasis-directed therapy group vs 3 and 6 occurrences in the surveillance group.
Quality of life assessed by the European Organization for Research and Treatment of Cancer QLQ-C30 and QLQ-PR25 indicated similar outcomes at 3-month and 1-year follow-up.
Grade 1 adverse events occurred in 6 patients (19%) in the metastasis-directed therapy group, with no grade ≥ 2 adverse events being observed.
The investigators concluded, “ADT-free survival was longer with metastasis-directed therapy than with surveillance alone for oligorecurrent [prostate cancer], suggesting that [metastasis-directed therapy] should be explored further in phase III trials. “
The study was supported by Kom op tegen Kanker.
Piet Ost, MD, PhD, of the Department of Radiotherapy, Ghent University Hospital, is the corresponding author for the Journal of Clinical Oncology article.
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