In a digital rectal examination (DRE), a health care provider examines your rectum with a lubricated, gloved finger. Although a DRE is often included as part of a routine physical exam, it’s not recommended as a stand-alone test for colorectal cancer. This simple test, which is not usually painful, can find masses in the anal canal or lower rectum. But by itself, it’s not a good test for detecting colorectal cancer because it only checks the lower rectum.