Role of palliative radiotherapy in unresectable intrahepatic cholangiocarcinoma: population-based analysis with propensity score matching

Feng Shao,* Wei Qi,* Fu Tao Meng,* Lujun Qiu, Qiang Huang Department of Biliary-Pancreatic Surgery, Anhui Provincial Hospital Affiliated with Anhui Medical University, Hefei, Anhui, People’s Republic of China *These authors contributed equally to this work Background: This population-based study evaluated the overall (OS) and cancer-specific survival (CSS) benefit from palliative radiotherapy (RT) in patients with unresectable intrahepatic cholangiocarcinoma (ICC). Methods: We queried The Surveillance, Epidemiology, and End Results (SEER) database for the patients with unresectable ICC diagnosed from 1973 to 2013. Propensity score–matched analysis was performed to reduce the impact of the selection bias between the palliative RT group and the nonpalliative RT group. Kaplan–Meier survival curves were used to estimate the survival outcome before and after propensity score matching. OS and CSS were compared between patients with and without palliative RT using univariate and multivariate Cox proportional hazards regression analyses. Results: A total of 4,027 of 15,803 patients diagnosed with ICC were included in this study. Of those, 847 (21%) patients underwent palliative RT, whereas 3,180 (79%) did not. In the unmatched population, patients treated with palliative RT had improved OS and CSS relative to those treated without palliative RT (adjusted HR =0.9065, 95% CI =0.8360–0.982, P=0.01735) and CSS (adjusted HR =0.8874, 95% CI =0.8160–0.9652, P=0.00532). After propensity score matching, palliative RT was associated with a significantly improved OS (adjusted HR =0.8544, 95% CI =0.7722–0.9453, P=0.00228) and CSS (adjusted HR =0.8563, 95% CI =0.7711–0.9509, P=0.0037). Conclusion: Palliative RT seems to improve the prognosis of patients with unresectable ICC. Keywords: radiation therapy, SEER, unresectable intrahepatic cholangiocarcinoma