The prognosis ofⅣ stage colorectal cancer patients is poor, and it is controversial to select adaptive surgical strategy for them. This work is aimed to systematically evaluate the prognostic impact of Ⅳ stage colorectal cancer patients who accepted different surgical strategies based on a large population.

We selected 13 077 patients diagnosed with Ⅳ stage colorectal cancer in 2010~2015 from National Cancer Institute′s Surveillance, Epidemiology, and End Results (SEER) dataset. They were divided into four groups as follows: no surgery group, primary site surgery group, metastatic site surgery group, all surgery group, and we analyzed the prognosis of patients with four surgical strategies and further explored the effect of chemotherapy on surgical strategy.

The median survival time (MST) of the four groups were 11, 18, 20, 31 months, respectively (P<0.001). The Cox proportional hazards model showed that primary site surgery group, metastatic site surgery group, all surgery group had a better prognosis than no surgery group, with hazard ratios of 0.640 (95%CI, 0.605~0.677; P<0.001), 0.592 (95%CI, 0.424~0.828; P=0.002), 0.371 (95%CI, 0.343~0.401; P<0.001) , respectively. And in the no (unknown) chemotherapy population, all surgery group (MST=6 months) had a survival benefit compared with primary site surgery group (MST=5 months, P<0.001); metastatic site surgery group (MST=4 months) had a similar survival with no surgery group (MST=2 months, P=0.236). In the chemotherapy population, different results were attained, all surgery group (MST=36 months) had a survival benefit compared with primary site surgery group (MST=25 months, P<0.001); metastatic site surgery group (MST=22 months) had a better survival than no surgery group (MST=16 months, P=0.015). Besides, the chemotherapy group (MST=25 months) had a better survival compared with no (unknown) chemotherapy group (MST=4 months, P<0.001).

Patients who underwent surgery for stage IV colorectal cancer had better overall survival than the no surgery group. The selection of chemotherapy factor would affected patients′ prognosis, in the no (unknown) chemotherapy population, we should avoid metastatic site surgery, however, in the chemotherapy population, metastatic site surgery would bring a better survival. And it proved that chemotherapy is good for patients with stage Ⅳ colorectal cancer.