The Clinical Impact of the Sum of the Maximum Standardized Uptake Value on the Pretreatment with <sup>18</sup>F-FDG-PET/CT in Small-Cell Lung Cancer

Abstract

<b><i>Objectives:</i></b> The aim of this study was to investigate the clinical significance of the sum of the maximum standardized uptake value (sumSUV<sub>max</sub>) on pretreatment positron emission tomography/computed tomography (<sup>18</sup>F-FDG-PET/CT) in newly diagnosed small-cell lung cancer (SCLC). <b><i>Methods:</i></b> We retrospectively analyzed 145 SCLC patients from March 2005 to June 2013 who underwent pretreatment <sup>18</sup>F-FDG-PET/CT. The sumSUV<sub>max</sub> was assessed in all malignant lesions up to a maximum of 5 lesions and a maximum of 2 lesions per organ according to RECIST 1.1. <b><i>Results:</i></b> A significant difference was found between the low and high sumSUV<sub>max</sub> groups (low vs. high sumSUV<sub>max</sub>, 91.5 vs. 77.3%; p = 0.018) in the response rate (RR) following frontline platinum-based chemotherapy. The group with low sumSUV<sub>max</sub> showed significantly better overall survival (OS; p < 0.001) as well as better progression-free survival (PFS; p < 0.001) compared with the group with high sumSUV<sub>max</sub>. Moreover, multivariate analysis revealed that a high sumSUV<sub>max</sub> alone was an independent poor prognostic factor for OS (hazard ratio 2.676; 95% confidence interval, 1.674-4.277; p < 0.001). <b><i>Conclusions:</i></b> This study showed that the sumSUV<sub>max</sub> adopted from RECIST 1.1 on pretreatment <sup>18</sup>F-FDG PET/CT was significantly correlated with response to treatment, OS, and PFS in patients with SCLC.