The combination of systemic chemotherapy and local treatment may improve the survival of patients with unresectable metastatic colorectal cancer.

With the development of systemic chemotherapy, the survival time of patients with advanced colorectal cancer (CRC) has increased. In addition, local treatments, such as microwave ablation and radioactive seed implantation, have been shown to be effective. However, the number of studies reporting on the effect of systemic chemotherapy combined with local treatments is limited. The present study was conducted to determine the effect of local treatment combined with systemic chemotherapy in patients with initial unresectable metastatic CRC (mCRC). Clinicopathological and follow-up data from 273 patients with initial unresectable mCRC between April, 2007 and October, 2013 were retrospectively analyzed. A total of 51 patients received minimally invasive treatments combined with systemic chemotherapy and 39 patients achieved tumor-free survival (TFS). The median TFS time was 9 months (range, 2-45 months); the median overall survival (OS) time was 40 months (range, 12-108 months). In patients who did not achieve TFS, the OS was 37 months. Thus, patients who achieved TFS exhibited a significantly longer OS compared with those who did not achieve TFS (P=0.049). The results of the univariate analysis demonstrated that certain characteristics, such as the number of lesions and maximum tumor diameter, were associated with the achievement of TFS. The patients assessed herein achieved TFS in response to local treatments combined with systemic chemotherapy. Furthermore, the achieved TFS provided an OS benefit.