Clinical Significance of Quantitative FDG PET/CT Parameters in Non-Small Cell Lung Cancer Patients

BACKGROUND: An initial evaluation of non-small cell lung cancer (NSCLC) patients with 18F- fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) scan can modify treatment planning. We investigated the clinical significance of FDG PET/CT quantitative parameters (QPs) in NSCLC patients. MATERIALS AND METHODS: We included 125 NSCLC patients for initial staging FDG PET/CT scan. The primary tumor (T), regional lymph node metastases (N), and distant metastases (M) were evaluated on FDG PET/CT images. QPs, including standard uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were calculated separately for each T, N, and M lesion and also for the whole body. Statistical analysis through SPSS version 22 was used to evaluate the clinical significance of PET/CT QPs concerning primary tumor pathology characteristics, initial tumor stage, and patient’s prognosis. RESULTS: We followed the patients for 19.28 (±11.42) months. Considering primary tumor pathology, there was a significant difference in FDG PET/CT QPs, including primary tumor SUVmax (p=0.00), metastases SUVmax (p=0.014), whole-body MTV (p=0.045), and whole-body TLG (p=0.002). There was also a significant difference in QPs, including primary tumor SUVmax (p=0.00) and regional lymph node metastases SUVmax (p=0.048) when accounting for tumor initial stage. There was a significant prognostic value for the whole-body TLG (p=0.01) and a cut-off point of 568 was reached to differentiate better versus worse survival outcome. CONCLUSION: We demonstrated a statistically significant difference in FDG PET/CT QPs when accounting for primary NSCLC pathology characteristics and initial stage, as well as patient’s prognosis, and recommend incorporating QP values into clinical PET/CT reports.