Colorectal cancer can be prevented, and the first step to prevent colorectal cancer is to see if you are a high-risk group for colorectal cancer: 1. 30-40 years old or older, more common over 60 years old, with gastrointestinal symptoms; 2. with a history of colorectal cancer; 3. with precancerous colorectal lesions such as adenoma, ulcerative colitis, schistosomiasis; 4. with a family history of cancer, familial polyp disease, hereditary colon disease; 5. Those who have a history of pelvic radiotherapy; 6. Those who have a history of gallbladder or appendectomy. People with these high-risk factors should have regular medical checkups, annual fecal occult blood test and anal examination, and if necessary, colonoscopy. Meanwhile, to prevent colorectal cancer, it is important to know that on the one hand, most colorectal cancers develop from polyps, and on the other hand, most early cancers can be completely cured. Therefore, the main way to prevent colorectal cancer is to find colorectal polyp lesions or early cancerous lesions in the colon. There are various types of colorectal polyps, and only some of them develop into colorectal cancer, and even then this is a long process, thus giving us ample time for intervention. However, clinically, colorectal polyps are asymptomatic. Many patients have already turned into colorectal cancer by the time they develop symptoms. Therefore, we are required to perform a physical examination to detect these colorectal polyps when they are asymptomatic. Those who are over 35, especially those with gastrointestinal cancer in their family line, are encouraged to have a colonoscopy. If polyps are found, they can be removed very simply under endoscopy and can be completely cured without surgery or chemotherapy. And it is important to have the polyps evaluated by an experienced doctor to determine the chance of such polyps becoming cancerous or to determine the time for follow-up review. Colonoscopy is an important tool for early screening of colorectal cancer, but public compliance is poor. In the United States, colonoscopy is recommended for all people over 55 years of age, and the screening rate is only 30% to 50%, and it is even lower in China. If colorectal cancer is detected, early standardized treatment can also improve the survival rate. At present, the 5-year survival rate of colorectal cancer in high-level hospitals in China is 50%-60%, which is comparable to the international level, but the 5-year survival rate in some hospitals is only 20%-30%. Therefore, it is especially important to promote the standardized treatment of colorectal cancer according to the treatment standard and expert consensus. The ease of metastasis to the liver is one of the characteristics of colorectal cancer, and the search for the mechanism of metastasis is the focus of the industry. It has been found that many genes are highly expressed in colorectal cancer cells and receptors for these genes exist in the liver. The number of cancer cell exosomes in the blood of colorectal cancer patients is significantly higher than that of the healthy population, and it is possible to develop corresponding antibodies to block the migration of exosomes to target organs through more in-depth molecular biology studies. By detecting the quality and quantity of tumor cell efflux bodies in blood, it can also help to assess the efficacy and guide the drug use for individualized treatment.