An Investigation of the Relationship Between 18F-FDG PET/CT Parameters of Primary Tumors and Lymph Node Metastasis in Resectable Non-small Cell Lung Cancer

Abstract

Background: Mediastinal lymph node metastasis is an important prognostic factor in non-small cell lung cancer (NSCLC) patients without distant metastases. 18F-2-fluoro-2-deoxy-D-glucose Positron Emission Tomography/Computed Tomography (18F-FDG PET/CT) is recommended for detecting and staging lymph nodes and distant metastases in NSCLC patients. Objective: This study aims to investigate whether maximum standardized uptake (SUVmax), mean standardized uptake (SUVmean), metabolic tumor volume (MTV), and tumor lesion glycolysis (TLG) values of the primary tumor measured by 18F-FDG PET/CT in resectable NSCLC can predict preoperative lymph node metastasis. Methods: This retrospective study included eighty NSCLC patients who underwent preoperative Positron Emission Tomography/Computed Tomography (PET/CT) for diagnosis and staging. The patients were stage I–III and had no distant metastases. Tumor metabolic parameters such as SUVmax, SUVmean, MTV, and TLG at PET/CT imaging were measured for preoperative diagnosis and staging, and the postoperative pathology results of the patients were examined. The pathology results divided patients into two groups; with and without lymph node metastasis. The groups were compared with student's t-test and chi-square test with regard to 18F-FDG PET/CT tumor metabolic parameters and other parameters. Results: Fifteen (18.8%) patients were female, and 65 (81.3%) were male. According to the postoperative pathology results, while 30 (37.5%) patients had lymph node metastasis, 50 (62.5%) did not. There was a significant difference between the groups regarding tumor SUVmax and SUVmean values (p = 0.036, p = 0.045). Overall survival in the N0 group was significantly higher than in the N1 + N2 group (p = 0.034); median survival was 30.2 months in N0 group cases and 27.3 months in N1 and N2 groups. Conclusion: SUVmax and SUVmean values are significantly higher in patients with lymph node metastases than in patients without lymph node metastases, and this finding may provide useful information for predicting lymph node metastasis in patients with resectable NSCLC.