Colorectal cancer (CRC) patients with liver metastasis are a special group of patients who exhibit a poorer prognosis compared with CRC patients without distal metastasis [1]. Approximately 30 % of CRC patients are found to have distal metastases at first diagnosis, and approximately half of the CRC patients with distal metastases exhibit liver metastases [2]. Up to 80 % of liver metastases are unresectable due to extrahepatic disease or multiple metastatic liver nodules [2]. Despite the advancement on surgical techniques and systematic therapy over recent years, 2/3 of the patients may experience cancer relapse in a five-year period [3]. Therefore, patients with locally advanced unresectable CRC and/or multiple metastases are recommended for systematic therapy but not surgery [[4], [5]]. Nevertheless, the rest 20 % of CRC patients with liver metastasis may have localized primary cancer and solitary liver metastasis, which potentially can be cured with a radical surgery. It was reported that the 5-year survival rate ranged from 35 % to 58 % for patients with complete resection of both primary and liver metastatic lesion, higher than those who did not have a chance for curative surgery [6].

Although the broad utilization of radical surgery in stage IV CRC patients with liver metastasis greatly promotes the survival rate of the population, the prognostic and risk factors remain to be better understood. A series of clinicopathological factors have been reported to influence the prognosis of the patients, including cancer lymph node metastasis, cancer differentiation, surgery time point [7], the choice of surgery techniques [8] and the use of neoadjuvant therapy before surgery [9], etc. These factors exhibited combined influence on the prognosis of the patients, and therefore models for prognosis prediction have been established [7].

Although many factors have been proved to influence the patient long-term survival, genetic factors, especially the correlation between mutational status and patient prognosis, have much less been investigated. In the background of broader use of targeted therapy in treating locally advanced or metastatic CRC, the information of genetic alterations cannot be neglected. In order to clarify the mutational factors involved in the therapeutic response and prognosis of stage IV patients with liver metastasis who received radical surgery, we designed a study and investigated the putative prognostic and risk factors. For this, a subpopulation of CRC patients with liver metastasis who elected for radical surgery and subsequent adjuvant therapy were retrospectively recruited. Meanwhile, clinicopathological information was also collected, and patient prognosis information was collected. As such, we hoped to identify factors that may potentially predict the prognosis of these patients, with specific focus on the influence of mutational status. A model established with significant prognostic factors was expected to be applicable in the prediction of individual survival and risk.