Rectal adenoma is a benign tumor of the rectum, while rectal cancer is a malignant tumor of the rectum, the two are completely different diseases, the difference lies in: 1. the growth rate is different, rectal adenoma grows slowly, while rectal cancer grows rapidly. 2. the boundary is different, rectal adenoma has a clear boundary and is less prone to adhesions, while rectal cancer has an unclear boundary and is prone to adhesions with surrounding tissues, causing painful clinical manifestations. 3. The treatment methods are different: rectal adenoma can be treated well by surgery alone, while rectal cancer requires chemotherapy and radiotherapy in addition to surgery. 4. whether there is metastasis or not, rectal adenoma does not metastasize, while rectal cancer is prone to metastasis. 5. the harm is different: rectal adenoma has less impact on human body, while rectal cancer seriously endangers human health and affects life quality.