Bowel cancer can be divided into different types according to different classification methods, and the common types are as follows: First, according to the occurrence site, the intestine is composed of jejunum, ileum, cecum, appendix, colon, rectum and anal canal, and the more common occurrence sites of bowel cancer are mainly colon and rectum. Secondly, according to the pathology, it can be classified into augmentation type intestinal cancer, ulcerative type intestinal cancer and infiltrative type intestinal cancer. Third, according to histological classification, epithelial malignant tumors of the colon can be divided into papillary adenocarcinoma, tubular adenocarcinoma, mucinous adenocarcinoma, indolent cell carcinoma, undifferentiated carcinoma, adenosquamous carcinoma, squamous cell carcinoma and carcinoid carcinoma. In contrast, malignant tumors of the anal canal can be classified as squamous cell carcinoma, basaloid cell carcinoma, mucinous epidermoid carcinoma, adenocarcinoma, undifferentiated carcinoma, and malignant melanoma. Although the types of intestinal cancer are more diverse when classified according to histological types, adenocarcinoma is still predominant, accounting for roughly more than 90% of intestinal cancers.