Elective nodal radiotherapy versus focal SBRT/SABR treatment volumes for nodal oligorecurrent oligometastatic prostate cancer: systematic review

Abstract

Background: Radiotherapy (RT) is an emerging metastasis-directed treatment strategy for patients with nodal oligorecurrent prostate cancer (PCa). However, substantial heterogeneity exists in RT regimens, with some series reporting elective nodal radiotherapy (ENRT) and others delivering focal treatment to recurrent lymph nodes using stereotactic body radiotherapy (SBRT), also termed stereotactic ablative body radiotherapy (SABR). In this systematic review, we compared oncologic outcomes and toxicity across RT approaches for nodal oligorecurrent PCa, with the aim of defining the optimal RT target volume in this setting. Methods: We performed a systematic search of the PubMed database to identify articles reporting ENRT or SBRT for oligometastatic PCa with nodal recurrence. Results: Twenty-two articles were analyzed, including four prospective phase II trials (3 using SBRT and 1 using ENRT). Focal SBRT, delivered as involved-node, involved-site, or involved-field radiotherapy, was the most commonly used strategy, with 2-year progression-free survival (PFS) rates ranging from 16% to 58% and a very low toxicity profile. Improved PFS rates were observed with ENRT strategies (52% to 80% at 3 years) compared with focal SBRT, despite a slightly higher toxicity rate. One ongoing randomized phase II trial is comparing both modalities in patients with nodal oligorecurrent PCa. Conclusions: Because of large variability in practice patterns, the optimal RT treatment volume and strategy remain to be determined for nodal oligorecurrent PCa. Ongoing randomized trials and advances in translational research will help clarify best management for these patients.