The role of standardized uptake value (SUV) based 18F-fluoro-2-deoxy-D-glucose (FDg) emission tomography (PET) metabolic parameters in detecting mediastinal lymph node metastases in early-stage lung cancer patients

. Lung cancer ranks first among cancer-related deaths worldwide, with approximately 2.4 million new cases and 1.8 million deaths annually. Mediastinal lymph node metastases are the most common form of metastasis in NSCLC and are closely associated with the prognosis and treatment strategy of the patient. In this study, 295 patients who underwent FDG PET/CT imaging at ESOGÜ Faculty of Medicine, Department of Nuclear Medicine between 2013 and 2023, and who subsequently underwent surgery for early-stage NSCLC at the Department of Thoracic Surgery, were retrospectively evaluated. A total of 215 patients who met the inclusion criteria were analyzed for the role of SUV-based parameters, such as primary tumor size, SUVmax, MTV, TLG, and lymph node SUVmax, in detecting lymph node metastases. Additionally, the role of these parameters in distinguishing ADC and SCC subtypes was examined. The mean age of the patients was 67.54 years. When PET/CT results were compared with histopathological findings, the sensitivity and specificity of PET/CT in detecting lymph node metastases were calculated as 52.4% and 82.7%, respectively. The ROC analysis determined a threshold value of 4.74 for lymph node SUVmax, with a sensitivity of 88.4% and specificity of 78.3%. Primary tumor size and SUVmax were not significantly associated with lymph node metastasis. However, MTV (positive: 20.80 ± 22.66, negative: 16.61 ± 21.91), TLG (positive: 164.11 ± 220.75, negative: 132.18 ± 182.99), and lymph node SUVmax (positive: 5.71 ± 1.01, negative: 4.08 ± 1.05) were significantly higher in the lymph node-positive group. When comparing the ADC and SCC histological subtypes, significant differences were found in tumor size, tumor SUVmax, and TLG values. However, no significant differences were observed between the two groups in terms of lymph node SUVmax and MTV values. SUV-based PET parameters may effectively detect lymph node metastases and differentiate tumor subtypes in early-stage NSCLC. Their inclusion in clinical decision-making processes could potentially improve diagnostic accuracy.