Salvage Therapy for Locoregional Recurrence After Stereotactic Ablative Radiotherapy for Early-Stage NSCLC

Although isolated local (LRs) and regional recurrences (RRs) constitute a minority of post-stereotactic ablative radiotherapy (SABR) relapses, their management is becoming increasingly important as the use of SABR continues to expand. However, few evidence-based strategies are available to guide treatment of these potentially curable recurrences. On behalf of the Advanced Radiation Technology Committee of the International Association for the Study of Lung Cancer, this article was written to address management of recurrent disease. Topics discussed include diagnosis and workup, including the roles of volumetric and functional imaging as well as histopathologic methods; clinical outcomes after salvage therapy; patterns of recurrence after salvage therapy; and management options. Our main conclusions are that survival for patients with adequately salvaged LRs is similar to that for patients after primary SABR without recurrence, and survival for those with salvaged RRs (regardless of nodal burden or location) is similar to that of patients with de novo stage III disease. Although more than half of patients who undergo salvage do not develop a second relapse, the predominant pattern of second failure is distant, especially for RRs. Management requires rigorous multidisciplinary coordination. Isolated LRs can be managed with resection and nodal dissection, repeat SABR, thermal ablation, or systemic therapies. RRs can be treated with combined chemoradiotherapy, radiation or chemotherapy alone, or supportive services. Finally, regular and structured follow-up is recommended after post-SABR salvage therapy.