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 early stage 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 NSCLC were examined. Ninety-four percent of patients had biopsy proven disease, the remainder refused. The median biologic effective dose (BED) for the cohort was 100 Gy (range, 78-180 Gy). Recurrence was defined clinically by RECIST and FDG-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 year overall survival (OS) was 65%. The 2 year local recurrence free survival, locoregional recurrence free survival and distant metastatic free survival were 89%, 78% and 72%, respectively. Of those with locoregional failure, ten were treated with salvage SBRT at a median time of 10 months from prior SBRT. Six patients were treated with systemic chemotherapy and 2 patients were offered palliative care. All patients treated with salvage SBRT remained controlled at a median time of 12 months. Treatment was well tolerated with 2 patients experiencing grade 2 pneumonitis, 1 patient experiencing grade 3 chest 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 estimated median 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 initial definitive SBRT for early-stage NSCLC is a potential option.  Additional prospective data is needed.