Metabolic imaging metrics correlate with survival in early stage lung cancer treated with stereotactic ablative radiotherapy

Background and Purpose: To test whether F-18-fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET-CT) imaging metrics correlate with outcomes in patients with stage I non-small cell lung cancer (NSCLC) treated with stereotactic ablative radiotherapy (SABR). Material and Methods: Fifty-four patients with stage I NSCLC underwent pre-SABR PET at simulation and/or post-SABR PET within 6 months. We analyzed maximum standardized uptake value (SUVmax) and metabolic tumor volume defined using several thresholds (MTV50%, or MTV2, 4, 7, and 10). Endpoints included primary tumor control (PTC), progression-free survival (PFS), overall survival (OS) and cancer-specific survival (CSS). We performed Kaplan-Meier, competing risk, and Cox proportional hazards survival analyses. Results: Patients received 25-60 Gy in 1 to 5 fractions. Median follow-up time was 13.2 months. The 1-year estimated PTC, PFS, OS and CSS were 100, 83, 87 and 94%, respectively. Pre-treatment SUVmax (p = 0.014), MTV7 (p = 0.0077), and MTV10 (p = 0.0039) correlated significantly with OS. In the low-MTV7 vs. high-MTV7 sub-groups, 1-year estimated OS was 100 vs. 78% (p = 0.0077) and CSS was 100 vs. 88% (p = 0.082). Conclusions: In this hypothesis-generating study we identified multiple pre-treatment PET-CT metrics as potential predictors of OS and CSS in patients with NSCLC treated with SABR. These could aid risk-stratification and treatment individualization if validated prospectively. (c) 2012 Elsevier Ireland Ltd. All rights reserved.