Competing risks analysis of external versus internal radiation in patients with hepatocellular carcinoma after controlling for immortal time bias.

Purpose: In cohort studies on liver cancer, there are often immortal time bias and interference of competing risk events. This study proposes to explore the role of internal and external radiotherapy for hepatocellular carcinoma using SEER data, using a competing risk model and controlling immortal time bias.

Methods: Data of SEER from 2004 till 2015 was included.