Evaluation of relationship between maximum SUV measured on 18F-FDG PET/CT with tumor pathological types, size, lymph node metastasis and distant metastasis in non-small cell lung cancer

Background: Lung cancer is the most commonly diagnosed cancer, of which the non-small cell lung cancer (NSCLC) accounts for approximately 80% of the newly diagnosed lung cancer. The prognosis of lung tumors depends on early and accurate staging as well as the histopathological type of the tumor. It is suggested that NSCLC with different histopathological types and primary tumor sizes can elicit variable max.SUV values on 18F-fluorodeoxyglucose-positron emission tomography/computed tomography (18F-FDG) PET/CT with different lymph nodes and distant metastatic potential. In this study, we aim to evaluate the relationship between the maximum SUV measured on (18F-FDG) PET/ CT with tumor pathological type, primary tumor size, lymph node metastasis, and distant metastasis in NSCLC. Results: This is a cross-sectional analysis of the (FDG-PET/CT) findings of 40 patients with NSCLC. Statistical analysis is used to determine correlation between max.SUV and tumor size, with each pathological type, nodal (N) staging and distant metastasis (AM staging. The primary lung tumors histopathological types were 25 (62.5%) adenocarcinomas, 12 (30%) squamous cell carcinomas and 3 (7.5%) large cell carcinomas. The max.SUV and tumor size of the squamous cell carcinoma group were significantly higher than max.SUV of adenocarcinoma and large cell cancer groups (P= 0.000009). A significant positive correlation was found between the primary tumor max.SUV and tumoral size. Neither lymph node nor distant metastases involvement was correlated with tumor max.SUV. Conclusions: The tumor size and histologic subtype both strongly influence FDG uptake in lung cancer. Nonetheless, max.SUV cannot be regarded as a predictive of metastases or lymph node involvement.