Colorectal cancer, also known as colorectal cancer, is the most common tumor at present, accounting for the third place in the morbidity and mortality of all tumors, and the incidence rate of the population has reached 40/100,000, which means that every 10,000 people will have 4 people with colorectal cancer. Since there is no national colorectal cancer screening program in China, coupled with the lack of awareness of prevention of colorectal cancer among common people, more than 85% of colorectal cancer is found in middle and late stages of colorectal cancer in clinic, which has poor therapeutic effect and high therapeutic cost, and many patients need to undergo “artificial anus” surgery due to the late stage of the tumor, and the quality of life is poor. Poor quality of life after surgery. Precision medicine is a very fashionable concept in recent years, as an ordinary person, how to achieve the standard of “precision treatment” in the prevention and treatment of colorectal cancer? How to detect early colorectal cancer and reduce the frequency of colonoscopy? Since early colorectal cancer is often asymptomatic, screening for asymptomatic people is the most effective and economical measure to detect early colorectal cancer, improve the therapeutic efficacy of colorectal cancer and reduce the incidence rate of colorectal cancer. For general population, it is recommended that people over 40 years old should undergo an annual fecal occult blood test, and a complete colonoscopy every 3-5 years, in order to detect early colorectal cancer, and for pre-cancerous lesions, the following measures are recommended For pre-cancerous lesions, colorectal polyps can be treated to prevent colorectal cancer; for people with hereditary colorectal cancer, the age of screening for colorectal cancer should be advanced by 5-10 years, which means that fecal occult blood tests should be performed from the age of 30-35 years. Although fecal occult blood + colonoscopy is currently the most effective treatment for colorectal cancer, the specificity of fecal occult blood test is not very high, and some tests developed in recent years through molecular markers in the blood, such as miRNA, circulating tumor cells, etc., have low sensitivity and certain false positives; colorectal cancer screening through molecular markers of exfoliated cells in the feces is an important research development, the In 2014, a European study of 10,000 cases of fecal methylation DNA testing for colorectal cancer screening showed that its sensitivity for colorectal cancer diagnosis reached 80% and specificity reached more than 90%, suggesting that it is a very promising indicator for “precision prevention and treatment”. The American fecal DNA methylation marker test kit cologuard is already on the market, and several domestic research centers are also developing similar products, which will hopefully be on the market in a short period of time. 2.What treatments should be chosen after getting colorectal cancer? In the clinic, after colonoscopy, if colon lesions are found, more than 90% of them can be identified after biopsy, i.e. benign and malignant; then after hospitalization, in addition to the routine assessment of the general basic status, chest and abdominal CT should be carried out to find out the metastasis of liver and lungs as well as the metastasis of lymph nodes, and pelvic magnetic resonance examination may be recommended for rectal cancer in order to assess whether the tumor invades the rectal mesentery and whether the tumor is in contact with the anal muscles. For rectal cancer, pelvic magnetic resonance examination may also be recommended to assess whether the tumor invades the rectal mesentery and the distance between the tumor and the anal raphe muscle to determine the possibility of anal preservation and the need for preoperative neoadjuvant therapy. For preoperative evaluation of stage I and IIA rectal cancer and stage I to III colon cancer, surgery is generally preferred; for stage IIB rectal cancer, if the tumor is preoperatively staged as T3 or T4, neoadjuvant radiotherapy is recommended before considering surgery; for stage III rectal cancer, preoperative radiotherapy is recommended before surgery; for patients with liver or lung metastasis, if there is no colon obstruction, intestinal perforation or severe bleeding, neoadjuvant chemotherapy is needed first, and then surgical resection will be performed after the distant metastases have shrunk or transformed into resectable lesions. Under what circumstances do I need to use targeted therapeutic agents? Targeted therapy is an important advancement at present. The longest-used targeted therapeutic agents in the clinic are cetuximab, a monoclonal antibody targeting epidermal growth factor receptor (EGFR), and bevacizumab, a monoclonal antibody targeting angiogenic factor (VEGF). Cetuximab is only effective for K-RAS wild-type tumors, so mutation screening of the K-RAS gene is required prior to treatment. Bevacizumab treatment does not require genetic testing, but in addition to the risk of hypertension, embolism, etc., its use in the preoperative period has increased the risk of surgical bleeding, so in patients who have used bevacizumab, it is best to choose the surgery in the discontinuation of the drug after one month before proceeding. Targeted drugs for advanced patients with distant metastases can increase the chance of their transformation into resectable lesions when used preoperatively, so preoperative adjuvant chemotherapy combined with targeted therapy can improve the efficacy of stage IV colorectal cancer. Of course, for recurrent or advanced colorectal cancer, targeted therapy can also improve the therapeutic effect, increase the chance of radical resection and improve the therapeutic effect. Under what circumstances is stoma surgery (artificial anus) necessary? Patients with rectal cancer are most worried about whether to “divert” or not, i.e. to have artificial anus surgery. Generally speaking, if the tumor is above 150px from the anal verge for men and above 125px for women, the possibility of preserving the anus is above 90%, but the possibility of preserving the anus decreases in the following colorectal cancers, but the possibility of preserving the anus also depends on the operation. However, whether the anus can be preserved also depends on whether the tumor is more than 50px away from the lower incision margin after sufficient freeing during operation. If the lower incision margin is more than 50px but the anastomosis position is low, in order to reduce the risk of anastomotic leakage after operation, the doctor often suggests temporary stoma. In order to minimize the risk of anastomotic leakage after surgery, the surgeon will recommend a temporary stoma, which will be returned after the anastomosis has healed completely in 3-6 months. The need for anal preservation also ensures that the patient’s anal function is normal before surgery. Some older people with poor anal function before surgery are not suitable for low anal preservation surgery, which results in poor anal function and poor quality of life after surgery. Under what circumstances should radiotherapy be performed after surgery? How should the review be done? Patients who did not have radiotherapy before surgery, if the pathology suggests IIB or above after surgery, they need to have postoperative radiotherapy, the radiotherapy program usually chooses oxaliplatin+5-Fu or hirudin+oxaliplatin, and if there are conditions, they can be given targeted therapy at the same time, and the chemotherapy is usually for 4-6 cycles. After the end of chemotherapy, patients should undergo regular review, generally speaking, CEA and CA199 examination every 6 months, CT examination of chest and abdomen, and colonoscopy once in a year; the time of regular review should not be less than 5 years, and the screening of colorectal cancer is the same as that of ordinary people after 5 years. At present, there are more methods for colorectal cancer treatment, but the mainstream and evidence-supported treatment plan is surgery-based comprehensive treatment. Although some other treatments may have certain efficacy, their exact efficacy still needs further research to realize the precision treatment of colorectal cancer, which can improve the efficacy and reduce the medical cost.