【論文摘要】Reliability and Reproducibility of F-18-FDG PET Parameters for Prognostic Survival Analysis in Carbon Ion Therapy Treated Stage I Non-Small Cell Lung Cancer Patients

Suman Shrestha ； Tetsuya Higuchi ； Katsuyuki Shirai ； Azusa Tokue ； Shreya Shrestha ； Jun-ichi Saitoh ； Hiromi Hirasawa ； Tatsuya Ohno ； Takashi Nakano ； Yoshito Tsushima

《核子醫學暨分子影像雜誌》 32卷1期 (2019/03) Pp. 57-58

https://doi.org/10.6332/ANMMI.201903.OC9

摘要

Introduction: Carbon ion therapy has emerged as an alternative treatment modality in a few centers in the world for the patients of stage I non-small cell lung cancer (NSCLC), unwilling or unfit for surgery. Recently, there are reports of F-18-fluorodeoxyglucose (F-18-FDG) positron emission tomography (PET) parameters to have prognostic significance and predictive ability for survival analysis. However, the reproducibility may be a major concern. The aim of this study was to evaluate the intraobserver and interobserver variabilities of F-18-FDG PET parameters. Methods: Thirty-nine stage I NSCLC patients (29 male/10 females; 71.9 ± 8.3 years old) who had performed F-18-FDG PET/computed tomography (CT) in our university hospital before undergoing therapy, between June 2010 and October 2016, were enrolled in this study. Retrospectively, two observers measured the parameters independently at two different time points blindly. The parameters measured were standardized uptake values (maximum, SUVmax; peak, SUVpeak; average, SUVmean); volumetric parameters, i.e., metabolic tumor volume (MTV; using SUV of 2.5), total lesion glycolysis (TLG; using SUV 2.5), and 50% and 60% of the maximum intratumoral activity (TLG50 and TLG60); the maximum tumor size in CT images. Then, intraobserver and interobserver variabilities between the two observers were determined. Results: Pearson's correlation co-efficients were ＞ 0.98 for all F-18-FDG PET parameters tested for both intraobserver and interobserver variability analysis, while it was ＜ 0.950 to 0.849 and 0.883 in the cases of tumor size, respectively. In the regression analysis, the intercepts and slopes for F-18-FDG PET parameters were ＜ 0.09 and 0.99-1.02 for intraobserver, and -0.001 to ＜ 0.150 and 0.984-1.043 for interobserver agreement. While for tumor size, the intercepts and slopes were ＞ 2.10-3.99 and ＜ 0.88 for intraobserver, and ＞ 1.39 and ＜ 0.99 for interobserver agreement. The intraclass correlation between two observers were ＞ 0.99 for both time points in the cases of F-18-FDG PET parameters, although 0.938 and 0.952 at two times points for tumor size. Conclusions: F-18-FDG PET parameters were found to be highly reproducible in comparison to the tumor size measurement on CT.