Metabolic Burden Measured by 18F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Is a Prognostic Factor in Patients with Small Cell Lung Cancer

PURPOSE Evidence regarding the usefulness of (18)F-fluorodeoxyglucose positron emission tomography/computed tomography ((18)F-FDG PET/CT) in predicting the prognosis of non-small cell lung cancer is increasing. However, data on small cell lung cancer (SCLC) are scarce. The aim of this study was to evaluate the prognostic value of metabolic parameters measured using (18)F-FDG PET/CT in patients with SCLC. MATERIALS AND METHODS We conducted a retrospective review of 114 patients with pathologically proven SCLC (26 cases of limited disease and 88 cases of extensive disease) who underwent pretreatment (18)F-FDG PET/CT. The maximal SUV (SUVmax) was used quantitatively for determination of FDG PET activity. The SUVmax of the primary tumor (primary SUVmax), the sum of SUVmax values of malignant lesions (SUVsum), and the mean SUVmax of malignant lesions were calculated. RESULTS The patient population was subdivided using a median SUVsum value of 24.6. High SUVsum showed a significant association with known factors for poor prognosis, including higher neuron-specific enolase (p=0.010), CYFRA 21-1 (p=0.014), and extensive disease status (p=0.007). Patients with high SUVsum had significantly shorter median overall survival (6.6 months vs. 13.0 months, p<0.001) and progression-free survival (5.2 months vs. 8.0 months, p<0.001) than patients with low SUVsum. Results of multivariate analysis showed that SUVsum, chemotherapy cycles, and the response to first-line treatment were significant prognostic factors of survival. In contrast, mean SUVmax and primary SUVmax were not significant predictors of survival. CONCLUSION In this study, metabolic burden represented by SUVsum from pretreatment (18)F-FDG PET/CT was an independent prognostic factor in patients with SCLC.