The most urgent wish of a tumor patient is to get rid of the tumor as soon as possible! Is it true that the faster the surgery, the better it is? Regarding this question, there is at least one kind of tumor that is not necessarily better the sooner the surgery, and that is rectal cancer. The treatment of rectal cancer is a comprehensive treatment mainly based on surgery, but for cases with deeper tumors, pre-operative radiotherapy is needed before surgery for better long-term results and higher possibility of preserving the anus; there are also some very shallow cases that do not necessarily need surgery yet, and colonoscopic resection may also be sufficient. The choice of treatment plan and timing of surgery must rely on preoperative tumor malignancy grading and staging. Preoperative evaluation relies on colonoscopy, pathology, and also CT or MRI or ultrasound endoscopy, and for low rectal tumors, MRI is better than CT. a few cases may require a combination of tests, as in the case below. The following case may require surgical treatment by CT, but in combination with colonoscopy and ultrasound endoscopy, endoscopic treatment is usually sufficient: a 75-year-old man with a polyp-like mass on colonoscopy, a high-grade intraepithelial neoplasia on biopsy, and a 4 CM mass on CT scan, considered to be rectal cancer. Because the tumor was seen to have a tip during colonoscopy and the bowel lumen was closed during CT, it might be difficult to accurately assess the biased early lesion. We then applied for a colonoscopic ultrasound, which showed that the mass, although relatively large, was confined to the mucosal layer and could be removed endoscopically. The cost and time could only be greatly reduced by spending 1 more day and about 1000 RMB for the examination, but this tumor could be removed without major surgery. As seen from this typical case, a reasonable preoperative examination and evaluation is necessary to develop a reasonable treatment plan, which is a prerequisite to get the best treatment!