Therapy response evaluation with FDG-PET/CT in small cell lung cancer: a prognostic and comparison study of the PERCIST and EORTC criteria.

INTRODUCTION: Small cell lung cancer (SCLC) is an aggressive form of lung cancer with poor prognosis. Adequate staging and therapeutic evaluation is necessary for therapy planning. Fluorodeoxyglucose (FDG)-positron emission tomography (PET)/computed tomography (CT) has been shown to be useful for staging and therapy response evaluation. The European Organization for Research and Treatment of Cancer (EORTC) and Positron Emission Tomography Response Criteria In Solid Tumors (PERCIST) criteria were compared in the evaluation of response assessment and prognostic factors were defined in a cohort of SCLC patients.

METHODS: Twenty-nine consecutive patients with SCLC were included in this study. Sixteen patients had extensive disease and 13 had limited disease. All patients had chemotherapy, 21 had thoracic radiotherapy. FDG-PET/CT scans were performed before and after therapy to evaluate treatment response. Metabolic responses were assessed using the EORTC criteria and PERCIST criteria. Univariate and multivariate analysis were performed using a Cox model to investigate the association between progression-free and overall survival time with a number of covariates.

RESULTS: There was perfect concordance between the EORTC and PERCIST criteria. Eight patients had a complete metabolic response (CMR), 9 had a partial metabolic response (PMR), 5 had stable metabolic disease (SMD) and 7 had progressive metabolic disease (PMD). Overall survival time in patients with CMR was significantly longer compared with patients who did not have CMR. The initial or delayed CMR and post-therapeutic standardized uptake value corrected for lean body mass were significantly associated with overall survival.

CONCLUSION: CMR on post-therapeutic FDG-PET/CT in patients with SCLC is an important prognostic factor and may help decision making for therapeutic management.