03:45 PM Abstract No. 330 Assessing outcomes of Yttrium-90 radioembolization for biphenotypic hepatocellular-cholangiocarcinoma

Biphenotypic hepatocellular-cholangiocarcinoma (HCC-CC) is a rare type of primary liver cancer that carries a poor prognosis. Since most patients present at a stage too advanced for surgical resection, loco-regional liver directed therapy is often performed for palliative or downstaging purposes. The purpose of this study is to evaluate patient outcomes after Yttrium-90 radioembolization (Y90) in patients with HCC-CC. A retrospective review of patients with biopsy-confirmed HCC-CC treated with Y90 between 2012 and 2018 was performed. Hepatic response to Y90 was assessed on follow-up CT or MR using modified RECIST criteria. Univariate and multivariable stepwise cox regression analyses were used to evaluate the association between demographic and clinical factors and survival. Logistic regression was used to evaluate associations between clinical factors and response to treatment (complete/partial response vs stable/progressive disease), overall response, and disease control. 22 patients with HCC-CC (median age 67.1 years, 17 male) underwent a total of 29 Y90 treatments (5 with resin, 24 with glass microspheres). Survival data was available in 21 patients and hepatic response data available in 20 patients. Hepatic response was 15% complete response, 35% partial response, 20% stable disease, and 30% progressive disease (50% response rate, 70% disease control rate). Two patients were successfully downstaged or bridged to transplant and one to resection. Median overall survival was 9.3 months (range 2.5-31.0 months) from time of Y90. Bilobar disease was found to have a 3-fold increase in the hazard of survival (p = 0.03, HR: 3.252 95% CI 1.098, 9.361) on univariate analysis. The final multivariable stepwise cox regression model found nonresponse to treatment after Y90 to be associated with a 4-fold increase in the hazard of survival (p = 0.0274, HR: 4.649, 95% CI 1.187, 18.207). Y90 is a viable option for loco-regional control of HCC-CC with good response and disease control rates. Nonresponse to treatment and bilobar disease were associated with reduced survival after treatment.