The Highest Metabolic Activity on FDG PET Is Associated With Overall Survival in Limited-Stage Small-Cell Lung Cancer

We evaluated the prognostic value of (18)F-fluorodeoxyglucose positron emission tomography (FDG PET) parameters for limited-stage small-cell lung cancer (LS-SCLC). We retrospectively enrolled 59 LS-SCLC patients who underwent pretreatment FDG PET/CT. Various PET parameters were measured in all malignant lesions, and we recorded the highest maximum standardized uptake value (SUV(max)), and sum of metabolic tumor volume (MTV(sum)) and total lesion glycolysis (TLG(sum)). The relationship between the highest SUV(max) and volumetric PET parameters was evaluated. The prognostic significances of PET parameters and clinical variables were assessed using Cox's proportional hazard regression analysis. Overall survival (OS) and progression-free survival (PFS) were assessed by the Kaplan–Meier method. The SUV(max) of the highest metabolic lesion had a significant positive correlation with MTV(sum) and TLG(sum) (P < 0.001). Upon multivariate analysis, the highest SUV(max) was an independent predictor of OS (1 unit increase, hazard ratio [HR]: 1.133, P = 0.003) and MTV(sum) was a significant prognostic factor of PFS (10-cm(3) increase, HR: 1.027, P = 0.034) after adjusting for age, sex, performance status, tumor stage, and treatment modality. The highest SUV(max) was a prognostic factor for PFS with marginal significance (1 unit increase, HR: 1.078, P = 0.053). Patients with higher SUV(max) (≥11) were also characterized by a significantly shorter median OS (P < 0.001) and PFS (P = 0.002) compared with patients with lower SUV(max). The highest SUV(max) is an independent prognostic factor for survival in LS-SCLC patients. Therefore, the highest SUV(max) might be a possible imaging biomarker for risk stratification in LS-SCLC. A further study in a large cohort is needed to validate the prognostic significance of the parameter.