Hepatectomy is associated with survival in intrahepatic cholangiocarcinoma: An observational study by instrumental variable analysis

Liver resection (LR) is a major treatment modality in select patients with stage I-III Intrahepatic cholangiocarcinoma (ICC), yet many studies demonstrated low rates of resection. The aim of the present study is to evaluate whether increasing resection rates would result in an increase in average survival in patients with stage I-III ICC. Surveillance, Epidemiology, and End Results 18 registry database for 2004 through 2015 was retrieved for the present study. Propensity score matching was performed to eliminate possible bias. In addition, instrumental variable (IV) analysis was utilized to adjust for both measured and unmeasured confounders. Among 2341 patients with clinical stage I-III ICC, we identified 1577 (67.4%) and 764 (32.6%) patients who received no treatment or LR, respectively. In the multivariable adjusted cohort, a clear prognostic advantage of LR was observed in overall survival (OS) (P < .001) and disease-specific survival (DSS) (P < .001) compared to patients who received no treatment. Estimates based on the IV analysis indicated that patients treated with LR had a significantly longer OS (P < .001) and DSS (P < .001) after adjusting confounding factors. In IV analyses stratified by American Joint Committee on Cancer tumor stage, we found that the better survival effects of LR on OS and DSS were consistent across all subgroups. Our outcomes indicated that LR was associated with a survival benefit for marginal patients with stage I-III ICC.