Evaluating patterns of failure and salvage therapy for patients treated with primary stereotactic body radiation therapy for early stage non-small cell lung cancer

Abstract

Objective: The purpose of this study is to evaluate patterns of failure after stereotactic body radiation therapy for earlystage NSCLC and determine the role of salvage therapy on patient outcome. Methods: Eighty-two consecutive medically inoperable patients treated with definitive SBRT for early-stage NSCLCwere examined. Ninety-four percent of patients had biopsy proven disease, the remainder refused. The median biologiceffective dose (BED) for the cohort was 100 Gy (range, 78-180 Gy). Recurrence was defined clinically by RECIST andFDG-PET or by pathologic diagnosis. Results: The estimated median survival for the entire cohort was 29.2 months (range, 1-40.3). The estimated 2 yearoverall survival (OS) was 65%. The 2 year local recurrence free survival, locoregional recurrence free survival and distantmetastatic free survival were 89%, 78% and 72%, respectively. Of those with locoregional failure, ten were treated withsalvage SBRT at a median time of 10 months from prior SBRT. Six patients were treated with systemic chemotherapy and2 patients were offered palliative care. All patients treated with salvage SBRT remained controlled at a median time of 12months. Treatment was well tolerated with 2 patients experiencing grade 2 pneumonitis, 1 patient experiencing grade 3chest wall pain and 1 with rib fracture. OS was compared between 3 subgroups: no locoregional failure (n = 65),locoregional failure without SBRT salvage (n = 7) and locoregional failure with SBRT salvage (n = 10). The estimatedmedian survival 31.3 months, 14.3 months and 29.9 months, respectively (p = 0.007).Conclusion: In our single institution patient cohort, SBRT in the salvage setting for locoregional recurrences after initialdefinitive SBRT for early-stage NSCLC is a potential option. Additional prospective data is needed.