Prognostic Role of 18F-FDG PET/CT in Oligometastatic Non-Small Cell Lung Cancer: Preliminary Results from Single Center

Background: Oligometastatic non-small cell lung cancer (OMD NSCLC) represents a distinct clinical state with limited metastatic spread, where local ablative therapies (LAT) combined with systemic treatment may improve outcomes. Accurate staging and prognostic assessment are critical, with 18F-FDG PET/CT emerging as a valuable tool for detecting metabolically active tumor burden. Results: We retrospectively analyzed 38 patients with synchronous OMD NSCLC who received radiotherapy. All patients underwent 18F-PET/CT and brain imaging for staging. Semi-quantitative 18F-PET/CT parameters, including metabolic tumor volume (MTV) and total lesion glycolysis (TLG) of primary tumor and metastatic lesions, were measured and associated with progression-free survival (PFS) and overall survival (OS) using Cox proportional hazard models. The median PFS and OS were 8.28 and 21.62 months, respectively. Higher MTV and TLG values of metastases were significantly associated with shorter PFS and OS (p < 0.01). In multivariable analysis, TLG of metastases above the median remained an independent predictor of worse PFS (HR = 2.78, p = 0.031) and OS (HR = 3.12, p = 0.024), alongside clinical factors such as ECOG performance status 2 and having multiple metastases. The metabolic parameters of the primary tumor did not predict survival outcomes. Conclusions:18F-PET/CT-derived metabolic parameters, particularly the TLG of metastatic lesions, may provide significant prognostic information in oligometastatic NSCLC beyond clinical variables. These findings may support the integration of 18F-PET/CT metrics for future trials involving patients treated with LAT in oligometastatic NSCLC.