Anal fingerprinting is not necessarily able to exclude bowel cancer, anal fingerprinting is the most commonly used physical examination for doctors to exclude whether there is bowel cancer or not, which has the advantages of simplicity, ease of implementation, non-invasiveness and economy. Generally, if there is rectal cancer and the tumor is closer to the anal opening, the tumor of the intestine can be touched. In some cases, anal finger test cannot touch the bowel cancer, for example, the bowel cancer is in the early stage, the tumor is relatively small, or grows in the muscle layer of the bowel, there is also a situation that the tumor is far away from the anus, for example, colon cancer, then in the time of anal finger test, the tumor cannot be touched, and it is easy to have a leakage of the diagnosis, so just based on the anal finger test may not be able to exclude the bowel cancer.