Abstract
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Objectives: F-18 FDG uptake within primary tumor has been shown to correlate with aggressiveness and survival on PET studies of patients with NSCLC (Vesselle H, 2003). We investigated whether F-18 FDG uptake by primary tumor is a predictor of lymph node (LN) involvement in patients with non small cell lung cancer (NSCLC).
Methods: A total of 51 consecutive patients with pathologically proven NSCLC were underwent dual-phase FDG PET. All of patients was underwent a thoracotomy within 1 month of F-18 FDG PET study. Maximum standard uptake values at 1 hour (SUV1) and 2 hour (SUV 2) following the injection of F-18 FDG were determined, and the retention index (RI) was calculated by dividing the difference between SUV2 and SUV1 by SUV1 (RI=(SUV2-SUV1)/SUV X 100%). The predictive values of SUV1, SUV2 and RI were analyzed, along with the clinical parameters. (age(≥60 vs 60<), Sex(M vs F), tumor size(>3cm vs 3cm<), histology (adenocarcinoma vs nondenocaricnoma), and tumor differentiation (well/moderately vs poorly).
Results: The LN involvements were founded in 49%. In univariate analysis the tumor size, RI and histology were factors significantly associated with LN involvement (p<0.05). The best cut-off value for RI was 17. In multivariate analysis the tumor size and RI (>17) were factors significantly associated with LN involvement (P<0.001).
Conclusions: SUV2 and RI from dual-phase FDG-PET by the primary tumor was significant predictors for LN involvement. High RI in the primary tumor at presentation should prompt high suspicion and an aggressive search for lymph node metastasis.
- Society of Nuclear Medicine, Inc.