Integrated 18F-FDG PET/CT parameter defines metabolic oligometastatic non-small cell lung cancer.

AIMS: The purpose of this study was to define metabolic oligometastatic non-small cell lung cancer (NSCLC) by using the number of metastatic lesions and 18F-FDG PET/CT parameters. METHODS: One hundred twenty-four newly diagnosed stage IV NSCLC patients who received pretreatment 18F-FDG PET/CT examination were retrospectively analyzed. The maximum standardized uptake value (SUVmax) of primary and metastatic lesions and the collected clinical parameters were fed into the univariate and multivariate Cox proportional hazard model. Survival analysis was performed using Kaplan-Meier and log-rank test. RESULTS: In univariate analysis, the results revealed that histology, metastatic organ numbers, adrenal gland metastasis, SUVmax of both primary and metastatic lesions, lactate dehydrogenase, systemic treatment, and local treatment were significantly correlated with overall survival of stage IV NSCLC patients. Multivariate analysis demonstrated that SUVmax of primary lesions and systemic treatment were independent risk factors of stage IV NSCLC patients. The addition of primary lung cancer SUVmax to traditional method (only count the numbers of metastasis lesions) enhanced the identification of oligometastatic NSCLC and the C-index increased from 0.601 to 0.693. CONCLUSION: We developed a method for the definition of metabolic oligometastatic NSCLC, which combined the number of organs involved, the number of metastatic lesions, and the SUVmax of primary lung cancer.