Selection of studies. This flow-chart details the process used for the selection of studies included in the systematic review. Initially, the literature search yielded 774 studies. Seven hundred and six studies were excluded because they did not report transitional HCC-CC characteristics, surgical treatment or survival outcomes. Fifty-four duplicate, non-comparative, not specifying the classification system, not in English language, published before 2002 studies were excluded. Eventually, 14 studies were selected and analyzed by the authors. HCC-CC, hepatocholangiocarcinoma.