Pelvic Irradiation for Node-Positive Prostate Cancer After Prostatectomy: Long-Term Results of the Prospective PLATIN-4 and PLATIN-5 Trials

Abstract

Purpose: After radical prostatectomy (RP), adjuvant or salvage radiation treatment in node-positive prostate cancer is offered to prevent systemic disease. Prospective long-term survival and toxicity data on patients with radiation for nodal disease is still scarce. This study evaluates safety and feasibility of salvage radiotherapy to the pelvic lymph nodes in node-positive prostate cancer after RP. Methods: Between 2009 and 2018, 78 patients with lymph node recurrence after RP (PLATIN-4) or after RP and PBRT (PLATIN-5) were treated with salvage pelvic lymph node radiotherapy (PLNRT) with boost to the involved nodes as field abutment (PLATIN-5) and boost to the prostate bed (PLATIN-4).ADT was started two months prior to radiation and recommended for 24 months. Primary endpoint was safety and feasibility of the IMRT/IGRT technique based on the rate of treatment discontinuations and incidence of CTCAE grade 3+-toxicity. Secondary endpoints were progression free survival (PFS) and overall survival (OS). Results: No treatment discontinuations were reported in either trial. Median OS was not reached in PLATIN-4 and was 117 months in PLATIN-5. Median PFS was 66 months in PLATIN-4 and 39 months in PLATIN-5. Late grade 3+ genitourinary and gastrointestinal toxicity was observed in 4% of patients at 24-months of follow-up. Conclusions: Salvage radiotherapy to the prostate bed and the pelvic lymphatic drainage combined with long-term ADT is a curative treatment option for patients with node-positive prostate cancer after RP with excellent infield disease control. PLNRT as field abutment after PBRT is feasible with long-term survival without suffering from high-grade toxicity.