PS03.03 Salvage Therapy for Relapse after Stereotactic Body Radiation for Stage I Lung Cancer: Topic: Radiation Oncology

Abstract

To evaluate treatment outcomes of recurrent non-small cell lung cancer (NSCLC) following initial SBRT for stage I disease. Retrospective review of patients treated with SBRT for stage I NSCLC from 2007-2017 who were found to have relapsed. Recurrences were classified as local (initial treated lesion), lobar (outside the treated lesion but confined to one lobe), nodal (hilum or mediastinum), or distant. Out of 297 treated with SBRT, 61 patients were found to have recurrence including 5 local, 14 lobar, 18 nodal, and 24 distant. Local recurrences developed at a median 21.2 months (range 11.6-63.4) from SBRT, and salvage treatment included radiation with concurrent chemotherapy (2 patients), lobectomy (2 patients), or radiofrequency ablation (1 patient). Lobar recurrences developed in a median 12 months (1.3 to 44.2), and nodal recurrences developed with median 11.3 months (1.8 to 34.5). Of 7 patients treated definitively after lobar relapse, 6 patients developed subsequent distant or regional relapse. Four of 11 patients treated for nodal relapse were salvaged without subsequent relapse. Approximately 40% of patients with lobar or nodal relapse did not undergo salvage therapy often due to poor functional status. Treatment related grade 3 + toxicity was not reported for patients treated with definitive salvage therapy. Median overall survival was 51 months after local relapse, 16 months after lobar relapse, and 13.7 months after nodal relapse. Median survival was 46 months for patients receiving definitive salvage therapy for intrathoracic recurrence compared with 9.7 months for patients not treated definitively. Distant recurrences occurred with a median of 10.9 months (range 2.0-55.9) after SBRT, and median survival was only 6.2 months after distant relapse in this group. Salvage therapy is feasible in the majority of patients with local or locoregional relapse after SBRT for stage I NSCLC. The success of salvage therapy appears to correlate with site of relapse with an unexpected high rate of subsequent relapse in patients treated for lobar recurrence. Novel approaches should be considered for addressing systemic disease in this poor risk population of patients.