The increment in standardized uptake value determined using dual-phase ¹⁸F-FDG PET is a promising prognostic factor in non-small-cell lung cancer

Purpose: We aimed to determine whether the increment in the maximal standardized uptake value (SUVmax) of the primary lung tumour between the initial and delayed imaging by dual-phase ¹⁸F-FDG PET has prognostic value in patients with non-small-cell lung cancer (NSCLC). Methods: We reviewed the records of patients with NSCLC who underwent pretreatment dual-phase ¹⁸F-FDG PET/CT scans acquired at 1 h and 2 h after injection. The SUVmax increment (SUVinc) of the primary lung tumour was the 2-h SUVmax minus the 1-h SUVmax. Univariate and multivariate analyses were used to assess the prognostic significance of SUVinc, retention index, whole-body total metabolic tumour volume, whole-body total lesion glycolysis (TLGwb), 1-h SUVmax, 2-h SUVmax, gender, age, performance status, histological subtype, T stage, N stage and clinical stage. Results: The records of 187 consecutive patients were reviewed. The median follow-up time was 3.9 years. The estimated median progression-free survival (PFS) and overall survival (OS) were 1.3 years and 4.4 years, respectively. An SUVinc cut-off value of >1 had the best discriminative yield for PFS. The 3-year PFS and OS were 61.6 % and 87.8 % in patients with SUVinc ≤1 versus 21.1 % and 46.2 % in patients with SUVinc >1 (all P<0.01). Using the forward stepwise multivariate Cox proportional hazards model, SUVinc, TLGwb, and clinical stage were significant factors for PFS (all P<0.01). A subgroup analysis of 117 patients treated with surgery showed that SUVinc (P=0.02) and clinical stage (P<0.01) were significant prognostic factors for PFS. Furthermore, in stage I patients treated with surgery alone, SUVinc was the only significant prognostic factor (HR 28.07; 95 % CI 2.42 - 326.41). Conclusion: SUVinc determined from dual-phase ¹⁸F-FDG PET is a promising prognostic factor for NSCLC. It adds to the value of dual-phase ¹⁸F-FDG PET.