Additional Prognostic Value of Metabolic Parameters Measured by Dual Time Point Pretreatment F-18 FDG PET/CT in Patients with Intrahepatic Cholangiocarcinoma.

e15598 Background: The aim of this retrospective study was to determine whether delayed glucose metabolism assessed by dual time point F-18 FDG PET/CT provides additional prognostic information independent of established prognostic factors in patients with intrahepatic cholangiocarcinoma (IHCC). Methods: We reviewed retrospectively the medical records of 96 patients (men 57, women 39, mean age 66 ± 10 years) with pathologically proven IHCC. They underwent dual time point F-18 FDG PET/CT as part of a pretreatment workup from July 2012 to December 2017. For the analysis, patients were classified by age, sex, stage, serum CA19-9, early SUVmax (eSUV), delayed SUVmax (dSUV), delta SUVmax (ΔSUV, difference between early and delayed SUVmax) and histopathology (pCEA, p53, Ki-67 index). The relationship between FDG uptake and survival was analyzed using the Kaplan-Meier with log-Rank test and Cox’s proportional-hazard regression methods. Results: Median survival for all 96 study subjects was 303 days and median SUVmax was 7.2 (range: 2.5 – 21.7). The survival was found to be significantly related to eSUV ( p < 0.0001), age ( p = 0.017), LN metastasis ( p = 0.03) and p53 index ( p = 0.04) and multivariate analysis study revealed that the patients with a higher SUVmax ( p = 0.0001, 95%CI = 1.80 to 5.89, HR = 3.26), prescence of LN metastasis ( p = 0.031), higher age ( p = 0.044) and a higher p53 index ( p = 0.007) showed worse overall survival. In addition, we carried out a subgroup analysis targeting the 55 patients with delayed SUVmax to evaluate a prognostic value of delayed image parameter. In univariate analysis, dSUV (cut-offvalue 7.3, p = 0.0006) and ΔSUV (cut-off value 3.2, p = 0.035), age ( p < 0.0001) and sCA19-9 ( p = 0.018) showed significant correlation and dSUV was an independent factor of overall survival in multivariate analysis. ( p = 0.014, 95%CI = 1.30 to 10.7, HR = 3.74) And then, we analyzed combinations of eSUV, dSUV and ΔSUV each other to evaluate additional prognostic information. The result revealed that higher dSUV ( p = 0.0001, AUC = 0.68) and ΔSUV ( p = 0.0002, AUC = 0.71) showed a poorer overall survival although the eSUV of IHCC was low. Conclusions: Higher delayed SUVmax and ΔSUVmax on pretreatment dual time point F-18 FDG PET/CT can predict poorer survival and additional information of risk stratification in patients with IHCC.