Oligopelvis-Getug P07: A Multicenter Phase Ii Trial Of Combined Salvage Radiotherapy And Hormone Therapy In Oligorecurrent Pelvic Node Relapses Of Prostate Cancer

93 Background: Oligorecurrent pelvic nodal relapse of prostatic cancer is a challenge for regional salvage treatments. We conducted OLIGOPELVIS – GETUG P07, a phase II trial of combined salvage radiotherapy and hormone therapy in oligorecurrent pelvic node relapses of prostate cancer (NCT02274779). Methods: OLIGOPELVIS–GETUG P07 was a prospective multi-center phase II trial investigating high-dose salvage pelvic irradiation with an additional dose to the fluorocholine-based positron-emission-tomography (FCH- PET)-positive pelvic lymph nodes (PLN), combined with six-month androgen blockade (LH-RH agonist or antagonist injections). The prescribed dose was 54 Gy in 1.8 Gy fractions with up to 66 Gy in 2.2 Gy fractions to the pathological PLN. Toxicity (CTCAE v4) and complete response rates (PSA < 0.20 ng/ml) were analyzed. The main objective was to assess biochemical-clinical failure defined by a cluster of events including PSA progression (≥25 % and ≥ 2 ng/ml above the nadir) or clinical evidence of local or metastatic progression or post- treatment initiation of hormonal therapy or prostate cancer-related death. We hypothesized that salvage treatment would achieve a 2-year relapse-free survival of 70 %. Results: Seventy-four patients were recruited in fifteen French radiation oncology departments between August 2014 and July 2016. Seven were excluded before treatment because of violation of the inclusion criteria. The intention-to-treat analysis therefore included sixty-seven patients. Half of them had received prior prostatic/prostate bed irradiation. Median age was 67.7. Grade 2+ two-year urinary and intestinal toxicity were 10% and 2% respectively. At 2 and 3 years, 73.1 and 45.9% of patients achieved a persisting complete response respectively. After a median follow-up of 34 months, the 2-year progression-free survival rate was 77.6%. Median progression-free survival was 40.1 months. Conclusions: Combined pelvic salvage radiotherapy and hormone therapy allowed for prolonged tumor control in oligorecurrent pelvic node relapses of prostate cancer with limited toxicity. Clinical trial information: NCT02274779.