https://www.selleckchem.com/products/pf-04957325.html ould have otherwise extended beyond typical PTV margins.Purpose/objectives This study analyzes the outcomes and toxicity of stereotactic body radiation therapy (SBRT) as salvage treatment for recurrent non-small cell lung cancer (NSCLC). Materials/methods This retrospective analysis considered patients treated with thoracic SBRT and a history of prior external beam radiation therapy (EBRT), SBRT, or surgical resection for NSCLC. Follow-up included PET and CT imaging at 2-3 month intervals. Key outcomes were presented with the Kaplan-Meier method. Results 40 patients with 52 treatments were included at a mean 11.82 months after treatment with EBRT (21), SBRT (15), surgical resection (9), and SBRT after EBRT (7). Median imaging and clinical follow-up were 13.39 and 19.01 months, respectively. SBRT delivered a median dose of 40 Gy in 4 fractions. Median biologically effective dose (BED) was 79.60 Gy. Median GTV and PTV were 10.80 and 26.25 cc, respectively. Local control was 65%, with a median time to local failure of 13.52 months. Local control was 87% after previous SBRT but only 33% after surgery. Median overall survival was 24.46 months, and median PFS was 14.11 months. Patients presenting after previous SBRT had improved local control (p=0.021), and the same result was obtained including patients with SBRT after EBRT (p=0.0037). Treatments after surgical resection trended towards worse local control (p=0.061). Patients with BED ≥ 80 Gy had improved local-progression free survival (LPFS) (p=0.032), progression free survival (PFS) (p=0.021), time without any treatment failure (p=0.033), and time to local failure (p=0.041). Using the Kaplan-Meier method, BED ≥80 Gy was predictive of improved LPFS (p=0.01) and PFS (p less then 0.005). Toxicity consisted of 10 instances of grade less then 3 toxicity (16%) and no grade ≥3 toxicity. Conclusions Salvage treatment for recurrent NSCLC with SBRT was effective and well tol