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Purpose To investigate prognostic and risk factors for recurrence after stereotactic body radiation therapy (SBRT) in patients with stage I non-small cell lung carcinoma (NSCLC), focusing on dual time point [18]F-fluorodeoxyglucose positron emission tomography (FDG PET). Materials and methods We prospectively evaluated 57 patients with stage I NSCLC (45 T1N0M0 and 12 T2N0M0) who had undergone pretreatment FDG-PET/CT and were subsequently treated with SBRT. All patients received a whole-body PET/CT scan at 60 min and a whole-lung at 120 min after the injection. The maximum standardized uptake value (SUV) and retention index (RI) of the lesions were calculated. Local recurrence, regional lymph node metastasis, distant metastasis, and the recurrence pattern were evaluated. Cox proportional hazard regression analyses were performed to evaluate prognostic factors or risk factors of recurrence. Results During the median follow-up period of 27 months, local recurrence, regional lymph node metastasis, and distant metastasis were seen in 17 (30%), 12 (21%), and 17 (30%) of the 57 patients, respectively. The 3-year overall survival rate was 63.4%. SUV max did not affect any recurrence, DFS, OS, or CSS. RI significantly predicted higher distant metastasis (HR 47.546, p = 0.026). In contrast, RI tended to predict lower local recurrence (HR 0.175, p = 0.246) and regional lymph node metastasis (HR 0.109, p = 0.115). Conclusions SUV max at staging FDG-PET does not predict any recurrence, DFS, OS or CSS. In contrast, higher RI predicts higher distant metastasis and tended to predict lower local or regional lymph node metastasis.

and 779 cGy (SDZ 1012 cGy) in patients without ET (pZ 0.074). MPD per fraction was 727 cGy (SD Z 466) in patients with ET and 249 cGy (SD Z 255) in patients without ET (pZ 0.035). D5 cc per fraction was 482 cGy (SD Z 397) in patients with ETand 208 cGy in patients without ET (SDZ 265) p Z 0.1216). Table shows the characteristics of the RTOG dose constraints when used to predict toxicity in our patients. Conclusions: Lung SBRT is associated with a low rate of esophagitis but severe toxicity can occur at very high doses. Our study shows that higher maximum point dose and D5 cc are associated with esophageal toxicity. Respecting RTOG constraints has a high NPV for toxicity in our population.