Survival outcomes and progonostic factors of extrahepatic cholangiocarcinoma patients following surgical resection: Adjuvant therapy is a favorable prognostic factor.

This study was conducted to investigate survival and prognostic factors for extrahepatic cholangiocarcinoma (ECC) following surgical resection and evaluate the effects of postoperative adjuvant therapy (AT) on overall survival (OS). We retrospectively collected clinical and pathological data between March, 2008 and December, 2013. The Kaplan-Meier method and the COX regression model were used to evaluate the OS and prognostic factors of 105 postoperative ECC patients, of whom 32 had received AT. The patients were stratified into seven risk subgroups and the survival rates were compared within each subgroup between patients who received AT and those who did not. The results demonstrated a median OS of 17.6 months, with 1- and 3-year survival rates of 67.9 and 19.5%, respectively, for the entire cohort. On univariate analysis, preoperative cholangitis, non-R0 surgical margins, poor differentiation grade, stage 3/4 and lymphatic metastasis were identified as adverse prognostic factors. AT was not significantly associated with improved OS. However, the subgroup analysis revealed that the effect of AT was significant only in the lymphatic metastasis group (median OS, 21.6 vs. 10.4 months; and 3-year OS, 16.6 vs. 0%, respectively; P=0.02). The survival curves of the AT and non-AT groups were significantly different only for node-positive patients. The COX regression model identified lymphatic metastasis, surgical margins and AT as independent prognostic factors for ECC. A negative resection margin may reduce the mortality rate following surgery by 47%. By contrast, lymph node metastasis was associated with a 2.18-fold higher mortality rate for ECC patients. Postoperative AT contributed to a 0.45-fold mortality rate compared to non-AT ECC patients. Therefore, we concluded that AT is a favorable prognostic factor for ECC patients and it may prolong the survival of patients with lymphatic metastasis. Our data suggest that postoperative AT should be recommended for node-positive ECC patients.