Biological Selection in Liver Transplant Oncology: Current Indications and Limits for Hepatocellular Carcinoma, Cholangiocarcinoma and Colorectal Liver Metastases

Liver transplant oncology has moved beyond the blunt expansion of size-based criteria. The central question now is whether tumour behaviour during treatment can identify the uncommon patient whose disease remains transplantable. This review examines hepatocellular carcinoma, perihilar and intrahepatic cholangiocarcinoma, and colorectal liver metastases, with emphasis on the evidence and policy shifts most relevant to current practice. In hepatocellular carcinoma, downstaging is best understood as a biological stress test rather than a technical bridge, and alpha-fetoprotein trend, radiological response, and time under observation now refine morphology-based thresholds. In perihilar cholangiocarcinoma, the lesson is different but equally clear: Transplantation succeeds when diagnosis, neoadjuvant therapy, staging, and operative discipline are delivered as a protocol. In intrahepatic cholangiocarcinoma, trans-plantation has become credible in very early cirrhotic tumours and in exceptionally selected liver-limited disease with durable treatment response, although the evidence remains centre-specific. Colorectal liver metastases mark the sharpest frontier, where comparative data have made transplantation intellectually defensible but not routine. Across these indications, the common denominator is biological selection, transparent reporting of the denominator, and careful stewardship of a scarce graft. The field will advance less by indiscriminately broadening criteria than by more precisely defining which cancers, in which biological states, genuinely justify transplantation.

Keywords: Cholangiocarcinoma; colorectal carcinoma; hepatocellular carcinoma; liver transplantation; metastasis; organ transplantation.