Salvage metastasis-directed therapy versus elective nodal radiotherapy for oligorecurrent nodal prostate cancer metastases (PEACE V-STORM): a phase 2, open-label, randomised controlled trial.

backgroundVarious locoregional treatments exist for PET-CT-detected pelvic nodal oligorecurrences in patients with prostate cancer. We aimed to assess whether elective nodal radiotherapy (ENRT) to the pelvis would be superior to metastasis-directed therapy (MDT).

methodsPEACE V-STORM is a phase 2, open-label, randomised, controlled trial conducted in 21 hospitals in Australia, Belgium, Italy, Norway, Spain, and Switzerland. Eligible participants were aged 18 years or older, with WHO performance status 0-1 and a histologically confirmed initial diagnosis of adenocarcinoma of the prostate, with a PET-detected pelvic nodal oligorecurrence (up to five nodes) following radical local treatment. Patients were randomly assigned (1:1) to MDT or ENRT. Randomisation was done online by minimisation with randomisation factor 0·80 and was stratified by type of PET tracer (choline vs prostate-specific membrane antigen) and type of MDT used (salvage lymph node dissection vs stereotactic body radiotherapy or simultaneous integrated boost). Participants and researchers were not masked to treatment assignment. Patients in the MDT group had salvage lymph node dissection or stereotactic body radiotherapy (30 Gy in three fractions every other day), with 6 months of androgen deprivation therapy. Patients in the ENRT group received a 45 Gy dose in 25 fractions to the pelvis with a simultaneous integrated boost of 65 Gy to the PET-positive nodes or salvage lymph node dissection, with 6 months of androgen deprivation therapy. The primary endpoint was metastasis-free survival, defined as the time between randomisation and the appearance of a metastatic recurrence (any M1) on PET imaging or death due to any cause, and was analysed per modified intention to treat. This study is registered with ClinicalTrials.gov, NCT03569241, and the Swiss National Clinical Trials Portal, SNCTP000002947, and is active, not recruiting.

findingsBetween June 11, 2018, and April 30, 2021, 198 patients were screened for eligibility, 196 of whom were randomly assigned to MDT (n=99) or ENRT (n=97), with 190 evaluable patients (MDT n=97 and ENRT n=93). All patients were male. Data on race and ethnicity were not collected. Median follow-up was 50 months (IQR 42-58). 4-year metastasis-free survival was 63% (80% CI 56-69) in the MDT group and 76% (69-81) in the ENRT group (HR 0·62 [80% CI 0·44-0·86]; p=0·063). The most common grade 3 adverse events were urinary incontinence (six [6%] of 97 in the MDT group vs nine [10%] in the ENRT group) and diarrhoea (one [1%] in the MDT group vs two [2%] in the ENRT group). No treatment-related deaths occurred.

interpretationTo our knowledge, this is the first randomised trial for metachronous PET-detected nodal recurrences comparing two local treatment approaches (MDT and ENRT) in combination with 6 months of androgen deprivation therapy. By showing an improved metastasis-free survival with ENRT, this trial establishes ENRT as a potential standard treatment approach, awaiting a phase 3 trial confirming these results.

fundingMovember Foundation, Kom Op Tegen Kanker, Stichting tegen Kanker.