Colorectal cancer, also known as colorectal cancer, is the most common tumor at present, accounting for the third place of incidence and mortality of all tumors, and the population incidence rate has reached 40/100,000, which means that colorectal cancer occurs in 4 out of every 10,000 people. Since there is no national colorectal cancer screening program in China, and the general public is not sufficiently aware of the prevention of colorectal cancer, more than 85% of colorectal cancers are found to be in the middle and late stages, with poor treatment effect and high treatment cost, and many patients need to undergo “artificial anus” surgery due to the advanced stage of tumor, which results in poor quality of life after surgery. The quality of life after surgery is poor. 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? 1.How can we detect early colorectal cancer and reduce the number of colonoscopies? 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 efficacy of colorectal cancer and reduce the incidence of colorectal cancer, for the general population, it is recommended that people over 40 years old should undergo an annual fecal occult blood examination and a full colonoscopy every 3-5 years to detect early colorectal cancer, and for precancerous lesions -For people with hereditary colorectal cancer family, the screening age for colorectal cancer should be advanced by 5-10 years, which means that fecal occult blood test should be performed from 30-35 years old. 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 by molecular markers in blood such as miRNA and circulating tumor cells are less sensitive and have certain false positives; colorectal cancer screening by molecular markers of exfoliated cells in feces is an important research progress. In 2014, a European study on screening colorectal cancer by fecal DNA methylation testing in 10,000 cases showed that its sensitivity for colorectal cancer diagnosis reached 80% and specificity reached over 90%, suggesting that it is a very promising indicator for “precise prevention and treatment”. cologuard has been marketed, and several research centers in China are developing similar products, which will hopefully be marketed in the near future. 2.What treatments should I choose after having colorectal cancer? In clinical practice, after colonoscopy, if a colon lesion is found, more than 90% of the lesions can be determined after biopsy, i.e. benign or malignant; then, after hospitalization, in addition to the routine assessment of the basic systemic status, CT examination of the chest and abdomen should be performed to detect liver and lung metastases and lymph node metastases, and for rectal cancer, pelvic MRI may also be recommended to assess whether the tumor invades the rectal mesentery For rectal cancer, pelvic MRI may also be recommended to assess whether the tumor has invaded the rectal mesentery and the distance between the tumor and the levator muscle to determine the possibility of preserving the anus and the need for preoperative neoadjuvant therapy. For preoperative evaluation of stage I and IIA rectal cancer and stage I-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 For patients with colon obstruction, intestinal perforation or severe bleeding, neoadjuvant chemotherapy is needed first, and surgical resection will be performed after distant metastases have shrunk or transformed into resectable lesions. Under what circumstances do I need to use targeted therapy drugs? Targeted therapy is currently an important development. The longest used targeted therapeutic agents in clinical practice are cetuximab, a monoclonal antibody against epidermal growth factor receptor (EGFR), and bevacizumab, a monoclonal antibody against angiogenic factor (VEGF). Bevacizumab treatment does not require genetic testing, but it has an increased risk of surgical bleeding when used preoperatively in addition to the risk of hypertension and embolism, so in patients who have used bevacizumab, surgery should preferably be performed after one month of discontinuation of the drug. Targeted drugs can increase the chance of transformation into resectable lesions when used preoperatively for advanced patients with distant metastases, so preoperative adjuvant chemotherapy combined with targeted therapy can improve the efficacy for stage IV colorectal cancer. Of course, for recurrent or advanced colorectal cancer, targeted therapy can also improve the efficacy, increase the chance of radical resection and improve the outcome. Under what circumstances is stoma surgery (artificial anus) necessary? Generally speaking, if the tumor is more than 150px from the anal verge for men and 125px for women, the possibility of preserving the anus is more than 90%, but for colorectal cancer below, the possibility of preserving the anus will decrease. However, whether the anus can be preserved depends on whether the tumor is more than 50px away from the lower incisional margin after sufficient intraoperative freeing, if the lower incisional margin is less than 50px after freeing, permanent “rerouting surgery” is often performed. In order to reduce the risk of postoperative anastomotic leakage, a temporary stoma is recommended and the anastomosis will be returned after 3-6 months when it is completely healed. The need for anal preservation should also ensure that the patient’s anal function is normal before surgery. Some older people with poor preoperative anal function are not suitable for low anal preservation surgery and have poor postoperative anal function and quality of life. Under what circumstances should radiotherapy be performed after surgery? What should be done for review? Patients who did not undergo radiotherapy before surgery, if the postoperative pathology is suggested to be IIB or above, they need to undergo postoperative radiotherapy. Radiotherapy regimens are generally selected from oxaliplatin + 5-Fu or Siroda + oxaliplatin, and if conditions are available, targeted therapy can be given at the same time, and chemotherapy is generally 4-6 cycles. After chemotherapy, patients should undergo regular review, generally speaking, CEA and CA199 examination every 6 months, CT examination of chest and abdomen, and colonoscopy within one year; the regular review should not be less than 5 years, and after 5 years, the same colorectal cancer screening as ordinary people. 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 achieve precise treatment of colorectal cancer, which can both improve the efficacy and reduce medical costs.