Increasing Pretreatment Tumor SUVmean Is Associated With Local Regional Failure After Chemoradiation for Locally-Advanced Non-Small Cell Lung Cancer

Abstract

Local regional failure (LRF) after definitive chemoradiation for stage IIIA and IIIB non-small cell lung cancer (NSCLC) remains high. The purpose of this study was to determine if pre-treatment [F-18] fluoro-D-glucose-positron emission tomography (FDG PET) parameters are associated with LRF after chemoradiation. This IRB-approved retrospective study analyzed patients with stage IIIA and IIIB NSCLC treated with definitive chemoradiation between the years of 2006 and 2011 at Emory University Hospital. Patient and treatment characteristics were collected from electronic charts. The SUVmean, SUVmax, and SUVpeak of the primary tumor and involved lymph nodes were extracted from the pre-treatment FDG PET CT by a single user. Locoregional failure was defined as failure within the ipsilateral lung, hilum or mediastinum. Multivariate analysis for factors associated with LRF was performed using the Cox proportional hazard method. SUV parameters were analyzed as continuous variables. Sixty-one patients were identified. Median follow-up was 19 months. Eighteen percent of patients were treated with Intensity Modulated Radiation therapy (IMRT), 10% with 3D and IMRT techniques, and 72% with 3D conformal technique. Thirty-nine percent of patients received daily on board imaging (OBI). Median total RT dose for all patients was 66 Gy. Concurrent chemotherapy was delivered to 90% of patients. The median pre-treatment SUVmax, SUVmean, and SUVpeak values were 15.2 (6.6-50.1), 4.52 (2.2-9.04), and 13.7 (4.85-44), respectively. A LRF occurred in 36% of patients. Median time to LRF was 11.4 months. On multivariate analysis, increasing pre-treatment tumor SUV mean was significantly associated with LRF (HR: 1.77; 95% CI, 1.18-2.65; p < 0.01). Lower T stage (HR: 0.04; 95% CI, 0.004-0.51; p = 0.013), lower N stage (HR 0.038, 95% CI, 0.004-0.34, p < 0.01) and white race (HR: 0.266; 95% CI, 0.076-0.931; p = 0.04) were associated with a decreased risk of LRF. Other factors, including radiation technique, use of OBI, SUVmax, and SUVpeak were not significantly associated with LRF on multivariate analysis. Pretreatment FDG PET tumor SUVmean is associated with LRF after chemoradiation for stage III NSCLC, and warrants further investigation.