Postoperative rectal adenocarcinoma without chemotherapy can also consider radiotherapy for conservative treatment. For postoperative rectal adenocarcinoma patients without chemotherapy, radiotherapy can be considered as a conservative treatment. Radiotherapy is a kind of local treatment that kills tumor cells in the designated irradiation field by focusing rays. Postoperative radiotherapy is obviously less effective than preoperative radiotherapy, and it is only suitable for patients who have not had radiotherapy before surgery and whose pathological results after surgery show a high risk of local recurrence, such as positive periapical margins and metastasis in lymph nodes of the pelvic side wall. For postoperative rectal adenocarcinoma patients, the treatment includes supportive therapy, radiotherapy and chemotherapy, etc. The specific treatment should be carried out under the guidance of physicians.