TY - JOUR T1 - Comparison of Quantitative Methods on Interim FDG PET Regarding Efficacy Prediction of a Multi-kinase Inhibitor Therapy JF - Journal of Nuclear Medicine JO - J Nucl Med SP - 357 LP - 357 VL - 57 IS - supplement 2 AU - Ji In Bang AU - Yoojoo Lim AU - Seo Young Kang AU - Jin Chul Paeng AU - Sae-Won Han AU - Tae-You Kim AU - Gi Jeong Cheon AU - Dong Soo Lee AU - June-Key Chung AU - Keon Kang Y1 - 2016/05/01 UR - http://jnm.snmjournals.org/content/57/supplement_2/357.abstract N2 - 357Objectives Interim FDG PET is reportedly effective in response prediction of chemotherapy. However, there is no standard method for quantitative evaluation of interim FDG PET, particularly regarding cytostatic drugs such as multikinase inhibitors. We compared various PET quantitative methods, in terms of response determination and prognosis prediction.Methods A total of 44 metastatic colorectal cancer patients were enrolled in a clinical trial for regorafenib, a multikinase inhibitor, and included in this study. Basal and interim FDG PET/CT scans were performed before and 2 cycles after treatment. Standardized uptake value (SUV) and total lesion glycolysis (TLG) values using various isocontour margin thresholds (SUV 3.0, 4.0, and 20%-80% of the maximum SUV with increment 10%) were measured in each lesion. The values from target lesions (5 highest metabolic lesions, Targets A; or those of the RECIST 1.1 method, Targets B) were summed. Tumor progression was determined during follow-up according to the RECIST 1.1 method (progressed disease, PD; stable disease, SD; and partial remission, PR). Predictive values of the PET indexes were evaluated in terms of the final progression-free survival (PFS) using Cox regression analysis and log-rank test.Results Median follow-up was 18.2 months and median PFS was 5.4 months. On interim PET, changes in maximum SUV, peak SUV, and TLG with various margin thresholds were all significant in predicting PFS (P < 0.05). Among the tested indexes, the highest significance was exhibited by TLG with margin threshold of 40% of maximum SUV, which was measured from Targets A (P < 0.001). When responses were classified according to this TLG, PFS was significantly different between different response groups (P < 0.001, for each comparison between PD, SD and PR).Conclusions Interim FDG PET is an effective method for determining response to a multikinase inhibitor therapy, and the summed TLG from the highest metabolic lesions can be the most effective quantitative index. Further studies are warranted regarding the optimal 1cutoff value for this method. Key words: FDG, PET/CT, regorafenib, response criteria ER -