Modified response evaluation criteria in solid tumors and European Association for The Study of the Liver criteria using delayed-phase imaging at an early time point predict survival in patients with unresectable intrahepatic cholangiocarcinoma following yttrium-90 radioembolization.

PURPOSE: To investigate early imaging prognostic factors in unresectable intrahepatic cholangiocarcinoma (ICC) refractory to standard chemotherapy after yttrium-90 ((90)Y) radioembolization therapy.

MATERIALS AND METHODS: In an institutional review board-approved prospective correlative study, 21 consecutive patients with ICC refractory to standard chemotherapy underwent (90)Y radioembolization therapy. Target and overall Response Evaluation Criteria In Solid Tumors (RECIST), modified RECIST (mRECIST), and European Association for the Study of the Liver (EASL) treatment responses were assessed. The mRECIST and EASL criteria were modified for application on delayed phases of dynamic contrast-enhanced cross-sectional imaging studies. Conventional definitions for complete and partial response were applied; these responses comprised objective response. Restaging imaging was obtained at 1- and 3-month intervals until patient death. Survival analyses by Kaplan-Meier and log-rank proportional models including application of the landmark method to avoid lead-time bias were performed from the day of treatment. Significance was set at P < .05.

RESULTS: Median overall survival (OS) from the time of (90)Y therapy was 16.3 months (95% confidence interval, 7.2-25.4 mo). Significant differences between mRECIST and EASL versus RECIST were found when categorizing patients into responders and nonresponders (P < .001). Significantly prolonged OS was observed for patients with targeted objective response based on modified mRECIST and EASL criteria (P = .005 and P = .001, respectively) at 3 months. RECIST was not found to correlate with survival at 1- or 3-month follow-up.

CONCLUSIONS: Modified target mRECIST and EASL criteria that employ delayed-phase contrast enhancement at 3 months after (90)Y radioembolization therapy for ICC predicted OS. RECIST did not correlate with survival.