Proposal of a New Definition of "Very Early" Intrahepatic Cholangiocarcinoma-A Retrospective Single-Center Analysis.

Intrahepatic cholangiocarcinoma (ICC) is a rare disease with poor outcome, despite advances in surgical and non-surgical treatment. Recently, studies have reported a favorable long-term outcome of "very early" ICC (based on tumor size and absence of extrahepatic disease) after hepatic resection and liver transplantation, respectively. However, the prognostic value of tumor size and a reliable definition of early disease remain a matter of debate. Patients undergoing resection of histologically confirmed ICC between February 1996 and January 2021 at our institution were reviewed for postoperative morbidity, mortality, and long-term outcome after being retrospectively assigned to two groups: "very early" (single tumor ≤ 3 cm) and "advanced" ICC (size > 3 cm, multifocality or extrahepatic disease). A total of 297 patients were included, with a median follow-up of 22.8 (0.1-301.7) months. Twenty-one (7.1%) patients underwent resection of "very early" ICC. Despite the small tumor size, major hepatectomies (defined as resection of ≥3 segments) were performed in 14 (66.7%) cases. Histopathological analyses revealed lymph node metastases in 5 (23.8%) patients. Patients displayed excellent postoperative outcome compared to patients with "advanced" disease: intrahospital mortality was not observed, and patients displayed superior long-term survival, with a 5-year survival rate of 58.2% (versus 24.3%) and a median postoperative survival of 62.1 months (versus 25.3 months; = 0.013). In conclusion, although the concept of a "very early" ICC based solely on tumor size is vague as it does not necessarily reflect an aggressive tumor biology, our proposed definition could serve as a basis for further studies evaluating the efficiency of either surgical resection or liver transplantation for this malignant disease.