Patient outcome

The survival status of the 396 patients was assessed until December 2017. The primary outcome measure was overall survival (OS), which is defined as the period from the date of potentially curative liver resection for metastatic CRC until death. The secondary outcome was the disease-free survival (DFS), defined as the length of time from potentially curative liver resection to either the first recurrence or death. Contrast-enhanced computed tomography and magnetic resonance imaging were employed for evaluating the recurrence, and the inspection date was taken as the recurrence confirmation date. In patients without recurrence, the latest imaging inspection date was used as the censored date.