Prognostic Value of the Volumetric Parameters of Dual-Time-Point 18F-FDG PET/CT in Non-Small Cell Lung Cancer Treated With Definitive Radiation Therapy.

OBJECTIVE. The purpose of this study is to assess the effectiveness of the volumetric parameters of dual-time-point imaging (DTPI) with 18F-FDG PET (DTPI FDG PET) in predicting the prognosis of patients with non-small cell lung cancer (NSCLC) treated with definitive radiation therapy (RT). MATERIALS AND METHODS. The records of consecutive patients who received definitive RT for NSCLC from April 2010 to April 2017 were retrospectively reviewed. Pretreatment DTPI FDG PET images were routinely obtained as part of the PET/CT examination. The maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) of the primary tumor (SUVmax-T, MTV-T, and TLG-T, respectively) and those of the primary tumor and lymph nodes (N) combined (SUVmax-TN, MTV-TN, and TLG-TN, respectively) were used as variables, and the percentage change in these parameters (change in SUVmax [ΔSUVmax], change in MTV [ΔMTV], and change in TLG [ΔTLG]) on DTPI FDG PET were analyzed. RESULTS. Of the 118 patients identified and reviewed, 59 met the study eligibility criteria. After a median follow-up of 23.3 months, the 3-year local control rate (LCR) and disease-specific survival rates were 53.5% and 45.0%, respectively. On multivariate analysis, significant predictors of LCR were TLG-T and change in TLG-TN (ΔTLG-TN), and significant predictors of disease-specific survival were adjuvant chemotherapy, treatment response, TLG-T, and change in TLG-T (ΔTLG-T). Low percentage changes in ΔTLG (< 41.0% for ΔTLG-T and < 32.0% for ΔTLG-TN) correlated with poor LCR and disease-specific survival. SUVmax and MTV were not significant predictors of both LCR and disease-specific survival. CONCLUSION. TLG and ΔTLG were significant prognostic factors in patients with NSCLC treated with definitive RT. In particular, a relatively low ΔTLG resulted in poor outcomes in terms of LCR and disease-specific survival.