Diagnostic value of FDG PET-CT in differentiating lung adenocarcinoma from squamous cell carcinoma

Lung cancer is the leading cause of cancer-related deaths worldwide. The combination of fluorine-18 fluorodeoxyglucose positron emission tomography (18F-FDG PET) and computed tomography (CT) has a major impact on the diagnosis, staging, treatment planning and follow-up of lung cancer patients. The maximum standardized uptake value (SUVmax) is an easily performed and most widely used semi-quantitative index for the analysis of FDG PET images and estimation of metabolic activity. This study aimed to investigate the role of PET/CT in differentiating adenocarcinoma (ADC), the most common lung cancer, from squamous cell carcinoma (SCC) by comparing FDG uptake measured as SUVmax. Between 2019 and 2022, 76 patients diagnosed with non-small cell lung cancer (NSCLC) at the Department of Pathology, Atatürk University Faculty of Medicine, with histopathologic evidence of adenocarcinoma or squamous cell carcinoma, underwent retrospective analysis using PET/CT scanning to measure PET parameters of the lesions and compare them with histopathology. Among 76 NSCLC patients included in the study, 43 (57%) were histopathologically diagnosed as ADC and 33 (43%) as SCC. SUVmax, SUVmean, metabolic tumor volume (MTV) and total lesion glycolysis (TLG) values of lesions in patients with SCC were statistically significantly higher than those in patients with ADC (p values 0.007, 0.009, 0.003 and 0.04, respectively). Lung SCC has higher metabolic uptake values than ADC, and PET/CT can be used to differentiate them.