Impact of primary tumor SUVmax on PET accuracy in mediastinal lymph node staging of non-small cell lung cancer (NSCLC)

BACKGROUND: Positron emission tomography (PET) using 18-fluorodeoxyglucose (18-FDG) is the primary imaging modality for mediastinal staging of lung cancer. Higher standardized uptake value (SUVmax) reportedly correlates with more aggressive and more readily detectable tumors. However, high-quality scientific evidence regarding the correlation between primary tumor SUVmax and PET performance in detecting mediastinal lymph node metastases remains limited. OBJECTIVES: To analyze the correlation between 18-FDG SUVmax and the diagnostic yield of PET, as well as the impact of clinical factors such as age, sex, body mass index (BMI), primary tumor lobar location, and histological type on this relationship. MATERIAL AND METHODS: This retrospective analysis utilized an institutional database and included a consecutive cohort of patients who underwent lung cancer surgery. RESULTS: In the overall cohort of 774 patients, PET demonstrated sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 59%, 76%, 27%, and 92%, respectively. Significant differences in sensitivity were observed between the SUVmax < 10 and SUVmax > 15 groups (p = 0.007), as well as between the SUVmax 10-15 and SUVmax > 15 groups (p = 0.001). Significant differences in NPV were found between the SUVmax < 10 and SUVmax 10-15 groups (p = 0.011). Logistic regression analysis revealed no association between the risk of false negative (FN) PET results for detecting N2 disease and patient characteristics, primary tumor lobar location, or histological type. CONCLUSIONS: Our study confirms that higher SUVmax values of the primary tumor correlate with improved PET diagnostic performance in assessing mediastinal lymph node metastasis. A novel finding of this study is that clinical variables such as age, BMI, sex, tumor location, and histological type did not significantly influence the risk of FN results. The main limitations of this study are its retrospective design and single-institution cohort, which may not fully represent the diversity of patient demographics, disease characteristics, and treatment practices across different healthcare settings and populations.