There have been many advances in the treatment of colorectal tumors in recent years, and the treatment options are still mainly surgical. The main progress in surgery is minimally invasive, but there are also many advances in adjuvant treatments other than surgery, i.e. radiotherapy and chemotherapy. In the past, these adjuvant treatments were administered after surgery, but now it has been found that adjuvant treatment with radiotherapy administered preoperatively in some cases can improve the certainty of clean surgical resection and long-term outcome. This preoperative administration of adjuvant therapy is called neoadjuvant therapy. In the colorectal setting, neoadjuvant therapy is used to improve the rate of radical surgical resection, increase the likelihood of anal preservation, reduce recurrence and metastasis, and prolong disease-free survival. So which cases require neoadjuvant therapy? That is to say, which cases are better for direct surgery and which are better for chemotherapy and radiotherapy first and then surgery? Neoadjuvant therapy has different indications between colon cancer and rectal cancer. Neoadjuvant treatment for colon cancer is mainly used in cases of colon cancer with simultaneous liver metastases, and in cases where simultaneous surgical resection is not appropriate, chemotherapy or interventional treatment is mainly used. In the case of operable cases, surgery should be performed first. For rectal cancer cases, neoadjuvant therapy is more important and more commonly used. Neoadjuvant therapy should be reasonably used according to the preoperative tumor stage. In cases with T-stage 3 or 4, or cases with enlarged lymph nodes, radiotherapy should be used before surgery. In case of obstruction, neoadjuvant treatment can also be done after releasing the obstruction by stent placement or stoma. The main forms of neoadjuvant treatment for rectal cancer are radiotherapy alone or radiotherapy and chemotherapy at the same time. Classic case: Low-grade rectal cancer, invading the anal raphe that controls the anus, requires preoperative radiotherapy according to the specification, not to preserve the anus, but to reduce the risk of recurrence after surgery. After 6 weeks of surgery after preoperative radiotherapy, it was found that the tumor shrank significantly and only a little scar could be seen from the intestinal cavity surface! Because of invasion of the anal raphe, a conventional combined abdominal perineal resection (APR, also called Mile’s surgery) cannot be done, but a combined abdominal perineal resection (ELAPR) via extra-anal raphe is performed. The abdominal surgery can be done minimally invasively under laparoscopy, while the tumor is done openly via the perineum.