After the pre-operative radiotherapy, rectal cancer patients are most anxious about when they can have surgery, after all, surgery is the main treatment for rectal cancer, and patients are worried that if they wait for more time, the disease will progress one more step. However, whether surgery can be done or not depends on the result of comprehensive assessment. Patients who undergo preoperative radiotherapy alone need to rest for 6~8 weeks after radiotherapy before surgery; because radiotherapy will cause local tissue congestion and edema, if surgery is performed too early, the edema will not subside, the surgical field will not be clear, and the chance of complications will increase. Patients who undergo preoperative radiotherapy-chemotherapy combination are usually treated with several groups of chemotherapy after radiotherapy to enhance the tumor-killing effect. The side effects of radiotherapy have been mentioned in the previous article. The most important reaction after chemotherapy is myelosuppression, which is visually manifested by a decrease in the patient’s white blood cells, red blood cells and platelets. When radiotherapy is combined with chemotherapy, after 2-3 cycles of chemotherapy, a review is needed to see the condition of the tumor lesions. If the effect is good, patients with 2-week regimen need to rest for 2 weeks after completing 3 chemotherapy cycles, after which they can have surgery; patients with 3-week regimen need to rest for 3 weeks after completing 2 chemotherapy cycles of chemotherapy before having surgery. Patients with poor chemotherapy results need to have 2 to 3 more cycles of chemotherapy, review while on chemotherapy, and then have surgery after resting for the appropriate amount of time when the treatment effect is apparent. Of course, patients also need to undergo a comprehensive evaluation before surgery, including blood and urine routine, coagulation function and biochemistry, lung function, electrocardiogram, echocardiography, abdominopelvic enhancement CT or MRI, colonoscopy, nutritional status, etc. Among them, the enhancement CT or MRI can see the effect of preoperative radiotherapy, and if the test results suggest tumor shrinkage, the doctor will then determine the results by colonoscopy. When the results of all examinations meet the requirements of surgery, the patient can be operated.