The incidence of rectal cancer continues to rise, and many patients with low-grade rectal cancer need to have their anus removed and wear an ostomy bag for life. After the removal of the anus, the patient’s life is prolonged but the quality of life is greatly affected, not only the complications of the stoma are difficult to avoid, but also many activities cannot be participated after the surgery. Therefore, it is the wish of many rectal cancer patients to be able to preserve the anus. In recent years, neoadjuvant radiotherapy for rectal cancer has been rapidly developed and popularized, and complete remission occurs in about 10-20% of patients after radiotherapy, that is, the tumor disappears after radiotherapy. In this case, the previous view was that this condition should also be operated, while recent findings show that these patients in complete remission can be operated without surgery, but only after rigorous screening and follow-up, and only in selected cancer research centers that are equipped to perform it.