Androgen deprivation therapy (ADT) is a mainstay in metastatic prostate cancer, while additional salvage radiotherapy may offer prolonged remission for patients with regional node relapses. We performed an open-label, phase II trial to assess the long-term outcomes and patterns of relapse of 6-months ADT and elective pelvic radiotherapy in men with oligorecurrent (<6) pelvic nodes in prostate cancer (Oligopelvis GETUG-P07).

We analyzed the 5-yr outcomes. Progression was defined as two consecutive prostate-specific antigen levels above the level at inclusion and/or clinical progression as per RECIST 1.1 and/or death from any cause.

Sixty-seven patients were recruited. The median follow-up was 6.1 yr (95%CI: 5.9-6.3). Grade 2+ 3-yr, 4-yr and 5-yr genito-urinary and gastro-intestinal toxicities affected 15%, 9%, 4% and 2%, 3%, 4% of non-progressive patients, respectively. 5-yr progression-free, biochemical relapse-free and ADT-free survivals were 39%, 31% and 64%, respectively. In total, 45 patients had progression and 38 had the following clinical progression: local (18%), N1 (29%), M1a (50%), M1b (32%) and M1c (11%).

Finally, combined elective pelvic radiotherapy and ADT appeared to prolong tumor control with limited toxicity. At 5 years, one third of patients had not relapsed biochemically. The major site of relapse was para-aortic lymph nodes.