Stereotactic Body Radiation Therapy Versus Surgery for Early Non-Small-Cell Lung Cancer in the Veterans Affairs System

Abstract

curative-intent conventionally fractionated thoracic external-beam radiotherapy (EBRT). Materials/Methods: Using an IRB approved registry of 141 patients treated with definitive intent lung SBRT (BED 100 Gy10) at our institution between 2010 and 2016, we identified 28 patients with a history of conventionally fractionated external-beam radiotherapy to the chest. All patients had a tissue biopsy or PET/CT prior to SBRT. Patients were treated on a linear accelerator-based SBRT system. CTCAEv4 scales were prospectively recorded during follow-ups and utilized for toxicity assessments. Kaplan Meier estimates were utilized for survival analyses. Results: Of the 28 patients included, median age was 71 years (Range [R]:55-84), 60% were female, median ECOG performances status was 1 (R: 0-3). 89.3% of patients received concurrent or sequential chemotherapy with their previous EBRT. 64.3% of lesions were not biopsied prior to SBRT treatment, 10.7% were squamous cell carcinoma, and 25.0% adenocarcinoma histology. The doses ranged from 3400 cGy to 6000 cGy in 1-8 fractions. 12 patients' (42.85%) disease retreated with SBRT was within previous EBRT treatment volume. At median follow up of 13.6 months (R: 4.5 e 62.1), the local in-field control was 92.9% with median time to failure 27.9 months (R: 26.8-29.0). 57.1% of patients progressed (median 7.8 months, R: 1.5-41.3) with first sites including 2 (7.1%) local in-field, 4 (14.3%) lobar out-of-field, 3 (10.7%) new primary, 6 (21.4%) regional, and 7 (25.0%) distant. The 2-year actuarial progression-free survival (PFS) was 25.0% and 2-year actuarial overall survival (OS) was 64.8%. There was minimal toxicity with 1 patient experiencing a grade 3 rib fracture and 2 patients with grade 2 pneumonitis. Conclusion: Our data suggest that lung SBRT is an effective and safe strategy after conventionally fractionated thoracic EBRT, for both in-field and out-of-field local recurrences.