More than half of colorectal cancer patients will have liver metastases Colon cancer and rectal cancer (together called colorectal cancer) have a common feature, that is, they can easily metastasize to the liver through blood, forming liver metastases. Data show that about 15%-25% of colorectal cancer patients have liver metastases when they are diagnosed with colorectal cancer, while another 15%-25% of patients have liver metastases within six months after radical surgery of the primary site of colorectal cancer. It can be seen that more than half of colorectal cancer patients will have liver metastases. For colorectal cancer patients, it is important to pay attention to the early diagnosis and active treatment of liver metastatic cancer. Gao Jun, Department of Hepatobiliary, Pancreatic and Splenic Surgery, West Hospital, Beijing Chaoyang Hospital, Capital Medical University Second, the occurrence of liver metastases is an important sign of the complexity of colorectal cancer. Colorectal cancer is usually easy to be removed if distant metastases do not occur and the cancer is confined to the intestine. However, if the cancer metastases to the liver, it is not so easy to completely remove the lesions because the metastases are usually multiple and scattered in the left and right liver. Therefore, liver metastasis is an important sign of the complexity of colorectal cancer and the most important cause of death of colorectal cancer patients. As mentioned above, liver metastases from colorectal cancer are often multiple lesions, and single lesions are less common. For lesions that are large and confined to one half of the liver, hepatic resection can be considered when the patient’s physical and economic conditions allow. The advantages of hepatic resection are that it can completely remove the visible and potential lesions in the liver; the disadvantages include: (1) it is only applicable to a small number of patients, and the majority (80%-90%) of liver metastases cannot be resected radically through hepatic resection; (2) the surgery is traumatic and requires high physical condition; (3) the cost is high; (4) it inevitably removes normal liver tissues of varying extent, which has a certain impact on liver function and quality of life; (5) it is difficult to be repeatedly applied, and it is difficult to be repeatedly applied for patients with large lesions. It is difficult to apply repeatedly, and there is nothing we can do to help the residual liver cancer foci. Chemotherapy alone is an indispensable treatment for liver metastasis of colorectal cancer. It plays an important role in removing local microscopic lesions remaining after resection of colorectal cancer and inhibiting the development of metastatic lesions in other organs such as liver. However, chemotherapy has its own limitations: (1) the toxicity and side effects are large, and the course of treatment is long, which is poorly tolerated by patients; (2) chemotherapeutic drugs are easily resistant and should not be applied repeatedly; (3) when liver metastases grow to more than 3 cm, chemotherapy alone can usually suppress or shrink liver metastases, but it is difficult to make them disappear completely. It can be seen that, for liver metastases that have developed to a certain extent, the efficacy of chemotherapy alone in treating liver metastases is not good. V. Radiofrequency ablation combined with chemical drugs has advantages in the treatment of liver metastases Radiofrequency therapy is one of the important advances in the treatment of liver cancer in recent years, and is a representative treatment mode of minimally invasive treatment for liver cancer. Its principle is to destroy cancer tissues through radiofrequency current, which causes the temperature in cancer tissues to reach about 105℃. The application of radiofrequency ablation in the treatment of liver metastatic cancer has many advantages in the following aspects: First, it has obvious complementary advantages when applied in combination with chemical drugs. For those larger lesions, they can be “eradicated” one by one by radiofrequency ablation. Those smaller lesions can be controlled by standard chemotherapy. Second, it can be repeatedly applied. Metastatic liver cancer often occurs in batches, for which RF ablation can be repeatedly applied almost without restriction, showing its advantages. Compared with liver resection, which can only be a “one-shot deal”, and compared with chemotherapy, which can only be repeated in a limited way, the repeatability of radiofrequency ablation has unparalleled advantages. Third, the treatment time is short, less invasive and less expensive. Only one radiofrequency ablation treatment requires only 2-3 days of hospitalization and 6 hours of bed rest after treatment, and the cost of one treatment is about 25,000 RMB. It can be seen that radiofrequency ablation can easily solve the current difficult problems in the treatment of liver metastatic cancer. Combined with chemical drugs, it can further enhance the efficacy, reduce the dosage of chemical drugs and their toxicity, and improve the quality of life of patients during treatment.