Liver transplantation for hepatocellular carcinoma: differences in pre-transplant radiology versus explant pathology and impact on survival.

Background: Suitability for liver transplantation in patients with hepatocellular carcinoma (HCC) is based on Milan imaging criteria developed several decades ago. We sought to compare pre-transplant imaging with explant liver histopathology in a national retrospective observational study.

Methods: All patients who underwent liver transplantation for HCC at the Scottish Liver Transplant Unit (2015-2020) were included. Per-lesion sensitivity of imaging, proportion of patients transplanted outwith UK transplant criteria and two-year survival outcomes were analysed.

Results: 140 patients were included. Per-lesion sensitivity was 70 % (38 % for lesions <10 mm). Histopathology of 36 (26 %) patients were outwith UK transplant criteria. 19 (14 %) livers contained >5 HCCs, median lesion size was 9 mm. 9 (6 %) livers contained cholangiocarcinoma. Two-year survival rates: cholangiocarcinoma 100 %, combined HCC-cholangiocarcinoma 100 %, HCC within criteria 90.8 %, HCC outwith criteria 87.5 %, >5 HCCs 77.8 % (p = 0.010).

Conclusions: Current pre-operative imaging for liver transplantation has suboptimal sensitivity, particularly for sub-centimetre lesions. A quarter of transplanted patients are subsequently found to be outwith transplant criteria on explant histopathology, but most have good short-term survival (including cholangiocarcinoma), except for patients with multi-focal small HCCs. Further research is needed to better identify this cohort and to explore whether transplant criteria should be revised.