Abstract LB-237: Response to loco-regional therapy as predictors of outcomes after transplantation for mixed hepatocellular cholangiocarcinoma

Abstract

Abstract Background: Mixed hepatocellular cholangiocarcinoma (HCC-CCA) is a rare primary malignancy of the liver which is distinct from hepatocellular carcinoma (HCC) or cholangiocarcinoma. HCC-CCA is presumed to have a poor prognosis and is not recommended for transplantation. The clinical and radiological presentation of HCC-CCA overlaps with HCC; thus, patients with these cancers may be mis-diagnosed as HCC and undergo liver transplantation, with the precise diagnosis ultimately determined on explant pathology. Patients undergoing transplant for presumed HCC receive loco-regional therapy (LRT), such as transarterial chemoembolization and radiofrequency ablation pre-transplant. Our goals were to (1) evaluate pre-transplant response to LRT, as predictors of recurrence and survival after transplant in HCC-CCA, and to (2) compare outcomes of transplant with adjuvant LRT in HCC-CCA and HCC. Methods: A retrospective study of 57 patients with presumed HCC who underwent liver transplantation and had pre-transplant LRT was performed. The study included 19 HCC-CCA cases and 38 HCC cases diagnosed on explant pathology, and individually matched (1:2) on age, sex, and Milan criteria. Response to LRT was determined by MRI performed before and after LRT. The response evaluation criterion in solid tumors (RECIST) was used to categorize treatment responses as “responders” if a patient had a complete or partial response or “non-responders” if a patient had stable or progressive disease. Recurrence rates, recurrence-free survival (RFS), and overall survival (OS) following LRT and transplant were compared between groups using Fisher’s exact tests. Results: The overall 1- and 3-year survival rates were 84% and 74% for HCC-CCA, and 95% and 87% for HCC, respectively. RFS at 1 and 3 years was 79% and 74% for HCC-CCA, and 92% and 87% for HCC (p-values >0.05). For HCC-CCA, one-year OS and RFS in LRT responders were 92% and 83%, whereas for LRT non-responders, OS and RFS were 71% each. In contrast, for HCC, one-year OS and RFS in LRT responders were both 97%, whereas among non-responders, they were 83% and 67%, respectively. At three years, OS and RFS in responders were 92% and 75% for HCC-CCA and 88% and 90% for HCC, respectively; whereas among non-responders, OS and RFS rates were 43% and 57% for HCC-CCA and 83% and 50% for HCC, respectively (all p-value >0.05). Conclusions: Short-term, post-transplant survival was poorer for HCC-CCA than HCC. However, OS among LRT responders for both cancers was similar. Response to LRT predicts favorable RFS in both HCC-CCA and HCC. Among non-responders, recurrence rate and RFS at three years were dismal and similar for both HCC-CCA and HCC, although OS is much lower for HCC-CCA patients. Response to pre-transplant LRT can be used for identifying HCC-CCA patients at high risk of recurrence and poor survival after liver transplantation. Citation Format: Yacob Y. Habboush, Samuel O. Antwi, Lori Chase, Tushar C. Patel. Response to loco-regional therapy as predictors of outcomes after transplantation for mixed hepatocellular cholangiocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-237. doi:10.1158/1538-7445.AM2017-LB-237