Response criteria in solid tumors (PERCIST/RECIST) and SUVmax in early-stage non-small cell lung cancer patients treated with stereotactic body radiotherapy

BACKGROUND The purpose of this study was to evaluate the prognostic impact of Positron Emission Tomography Response Criteria in Solid Tumors (PERCIST) and Response Evaluation Criteria in Solid Tumors (RECIST) and of pre- and post-treatment maximum Standard Uptake Value (SUVmax) in regards to survival and tumor control for patients treated for early-stage non-small cell lung cancer (ES-NSCLC) with stereotactic body radiotherapy (SBRT). METHODS This is a retrospective review of patients with ES-NSCLC treated at our institution using SBRT. Lobar, locoregional, and distant failures were evaluated based on PERCIST/RECIST and clinical course. Univariate analysis of the Kaplan-Meier curves for overall survival (OS), progression free survival (PFS), lobar control (LC), locoregional control (LRC), and distant control (DC) was conducted using the log-rank test. Pre- and post-treatment SUVmax were evaluated using cutoffs of < 5 and ≥ 5, < 4 and ≥ 4, and < 3 and ≥ 3. ∆SUVmax was also evaluated at various cutoffs. Cox regression analysis was conducted to evaluate survival outcomes based on age, gender, pre-treatment gross tumor volume (GTV), longest tumor dimension on imaging, and Charlson Comorbidity Index (CCI). RESULTS This study included 95 patients (53 female, 42 male), median age 75. Lung SBRT was delivered in 3-5 fractions to a total of 48-60 Gy, with a BEDα/β = 10Gy of at least 100 Gy. Median OS and PFS from the end of SBRT was 15.4 and 11.9 months, respectively. On univariate analysis, PERCIST/RECIST response correlated with PFS (p = 0.039), LC (p = 0.007), and LRC (p = 0.015) but not OS (p = 0.21) or DC (p = 0.94). Pre-treatment SUVmax and post-treatment SUVmax with cutoff values of < 5 and ≥ 5, < 4 and ≥ 4, and < 3 and ≥ 3 did not predict for OS, PFS, LC, LRC, or DC. ∆SUVmax did not predict for OS, PFS, LC, LRC, or DC. On multivariate analysis, pre-treatment GTV ≥ 30 cm3 was significantly associated with worse survival outcomes when accounting for other confounding variables. CONCLUSIONS PERCIST/RECIST response is associated with improved LC and PFS in patients treated for ES-NSCLC with SBRT. In contrast, pre- and post-treatment SUVmax is not predictive of disease control or survival.