For diagnosed rectal cancer, there are different treatment methods as follows 1. For polyp cancer with tip or stage 0 rectal cancer; submucosal cancer with tumor less than 2 cm, mucosa and mild infiltration: endoscopicmucosal resection (EMR) or transanalendoscopic tumor local excision (TEM) can be used. After the surgery, regular review and follow-up should be paid attention. It can be done without radiotherapy or chemotherapy. 2.For stage 0 rectal cancer, deep invasive submucosal cancer, stage II and III cancer with tumor larger than 3 cm, radical rectal cancer surgery, which is often referred to as Dixon or Miles surgery, is required. The specific way to be used depends on the site of the tumor. Regular review and follow-up after surgery. Adjuvant radiotherapy and chemotherapy will be decided according to the results of disease examination. 3.For stage IV rectal cancer (rectal cancer with distant metastasis and other conditions), there are different treatment methods as follows according to different situations. (1) If both rectal cancer and metastatic cancer can be removed, surgical resection is used. (2) For rectal cancer that both metastases and primary foci cannot be resected, treatment methods other than surgery (chemotherapy, radiotherapy, etc.) are used (3) For rectal cancer that metastases can be resected but primary foci cannot be resected, treatment methods other than surgery (chemotherapy, radiotherapy, etc.) are used (4) For rectal cancer that metastases cannot be resected but primary foci can be resected, surgery to remove primary foci can be considered and treatment methods other than surgery are used for metastases. For rectal cancer without heavy bleeding, high level of anemia, stenosis and perforation (metastases cannot be resected but primary foci can be resected), treatment methods other than surgery can also be used.