This is a retrospective cohort study conducted in Hunan Cancer Hospital. Patients (pts) with mCRC who had received at least the 2nd line treatment were eligible. Propensity score (PS) would be calculated to balance the baseline characteristics of two arms. Overall survival (OS) was set as the primary endpoint. From July 2019 to October 2022, 106 eligible pts in total were enrolled. According to the treatment received, 72 and 34 pts were respectively allocated into FP cohort and TB cohort.