Cholangiocarcinoma Prognosis Varies over Time Depending on Tumor Site and Pathology

Background: Cholangiocarcinoma is a relatively rare cancer that is difficult to diagnose and has a poor prognosis. Currently, knowledge concerning its etiology, tumor localization, and pathological features remains limited. The present study aimed to clarify the clinico-epidemiologic nature of cholangiocarcinoma with its clinical subtypes using the largest regional cancer registry in Japan.Methods: Using a regional cancer registry in Kanagawa prefecture, Japan, we estimated three-year and five-year survival rates of cholangiocarcinoma patients, who were classified into two groups: intrahepatic (i-CCA) and extrahepatic cholangiocarcinoma (e-CCA) cases. The hazard ratio for each subtype, including pathological tissue type and tumor site, was calculated.Results: During the period from 1976 to 2013, 14,287 cases of cholangiocarcinoma were identified. The prognosis markedly improved after 2006, when a new type of chemotherapy for cholangiocarcinoma was introduced in Japan. Patients with i-CCA were more likely to be younger, and less likely to undergo surgery than those with e-CCA. The prognosis of cases with i-CCA was poor compared to that of patients with e-CCA.Conclusion: In Japan, i-CCA was more likely to develop in younger people and to have a poor prognosis. The prognosis of both i-CCA and e-CCA cases markedly improved after 2006. The present study describes clinico-epidemiological features of cholangiocarcinoma that may be useful for determining therapeutic strategies for this disease.