Prognostic Factors and Treatment Strategies for Intrahepatic Cholangiocarcinoma from 2004 to 2013: Population-Based SEER Analysis

BACKGROUND: Seventy percent of intrahepatic cholangiocarcinoma (ICC) patients are inoperable. Treatment for unresectable patients is essential to improve poor survival. AIMS: We aimed to evaluate the prognostic factors for ICC patients, and investigate the potential treatment strategies for unresectable patients. METHODS: ICC patients were identified in SEER registry in 2004-2013. Univariate and multivariate Cox proportional hazard regression analysis were performed to evaluate the effect of treatment strategies. RESULTS: Of 2248 cases diagnosed in 2010-2013 and staged according to the American Joint Committee on Cancer (AJCC) 7th edition, 1706 (76.13%) did not receive cancer-directed surgery. This portion increased compared to those diagnosed between 2004 and 2009 and staged according to the AJCC 6th edition (72.87%). In addition, the percentage of stage 4 cases increased, while stage 3 cases decreased, because AJCC 7th staging system categorized both T4 and N1 patients into stage IV, which were previously categorized into stage III by AJCC 6th staging system. Patients with radiofrequency ablation (RFA) showed a poorer survival in 2004-2009 (P = .0213), but an almost the same survival as patients with tumor resection in 2010-2013 (P = .51), suggesting that RFA performed better in recent years. Lymphadenectomy showed protective effect for unresectable patients. Radiotherapy improved cancer-specific survival in non-surgery patients (P < .0001).The proportion of stage IV patients increased tremendously from 37.4% in 2004-2009 to 58.7% in 2010-2013. Among 1319 stage IV patients (2010-2013), surgery at distant metastatic sites improved cancer-specific survival. CONCLUSIONS: For unresectable tumors, RFA, radiotherapy, lymphadenectomy, and surgery of distant metastases showed significant benefits to improve cancer-specific survival.