Definition of anal Pap smear. An anal Pap smear can also show conditions that are not cancer, such as infection or inflammation. Also called anal Pap test. A rectal examination, commonly called prostate exam, is an internal examination of the rectum The DRE is inadequate as a screening tool for colorectal cancer because it examines less than 10% of the colorectal mucosa; sigmoidoscopy is. Anal Pap smears similar to those used in cervical cancer screening have been studied for early detection of anal cancer in high-risk.