The best timing of preoperative chemotherapy for liver metastases of colorectal cancer        XING Bao-cai, WANG Hong-wei. Department of Hepato-bilio-pancreatic Surgery I, Peking University School of Oncology，Beijing Cancer Hospital，Beijing 100142, China
Corresponding author：XING Bao-cai, E-mail：xingbaocai88@sina.com
Abstract    The combination of surgery and chemotherapy has become the standard treatment for patients with liver metastases of colorectal cancer. There is controversy that preoperative chemotherapy should be considered in patients with resectable liver metastases of colorectal cancer. The patients with prognostic factor of poor survival should be received preoperative chemotherapy. Surgery should be performed after a maximum of 6 cycles of preoperative chemotherapy. In patients with unresectable liver metastases, there is no question regarding the indication of chemotherapy. They should be carefully monitored and performed surgery as soon as the metastases become resectable. Surgery can be performed after 4 weeks from the last cycle of chemotherapy, and 6-8 weeks following chemotherapy plus bevacizumab.