A rectal exam, otherwise known as a digital rectal exam or DRE, is an examination of the inside of the rectum and can be one way to detect signs of colon cancer or other indicators that a colonoscopy may be necessary. During the procedure, a physician inserts a gloved, lubricated finger into the rectum to feel for abnormalities. No colon cleansing is necessary. The test happens quickly and usually does not hurt at all. However, the test can only detect problems in the lower rectal area, not the colon. Additional screening tests would need to be performed to find polyps or lesions deeper inside.
Rectal Exam Procedure
During a regular physical exam, after other tests and checks have been administered, a doctor or nurse will ask you to undress completely while he or she leaves the room for a few minutes. A paper hospital gown will be left in the room for minimal coverage.
When the doctor re-enters the room, you will need to position yourself in a way that the anus is accessible to the doctor. This may mean you will need to lie on your side on top of the examination table with your knees pulled toward your chest, to assume a squatting position on the table or to stand flat-footed on the floor while bent over. Some doctor’s offices may be equipped with an apparatus that allows patients to lie comfortably on their backs, at a slight tilt, while their feet rest on stirrups, giving the doctor access to the rectum and anal area between the patients’ legs.
The doctor will then use hands, protected with sterile latex gloves to prevent contamination, to spread the buttocks apart while he or she examines the external area surrounding the anus and perineum. If there are any signs of inflammation or abnormal growths, the doctor will be able to study them at this point of the exam. Common conditions detected on the external part of the colorectal area include rashes and hemorrhoids.
For the second, internal part of the rectal exam, the patient will be asked to relax while the doctor inserts his or her gloved finger into the rectum and through the anus, feeling the patient’s insides for signs of health problems. Most doctors will use a lubricator to allow smoother access. This part of the rectal exam lasts only about a minute.
If your doctor detects cancerous or even non-cancerous tumors during a rectal exam, it is possible that you have one of several health conditions. Patients checking for the following conditions may undergo a digital rectal exam as a preliminary screening test: colorectal cancer, hemorrhoids, prostate cancer in men and ovarian cancer in women. A digital rectal exam is often administered before a regular colonoscopy, as well.
Further Testing After A Rectal Exam
Talk to your GI doctor if you are experiencing constipation—rectal exams can also be used to evaluate the hardness of a patient’s feces. The exam also tests the tonicity of the anal sphincter, for patients who have experienced severe injuries or are having problems controlling their bowel movements. The test is often ordered in conjunction with routine blood tests such as fecal occult blood test (FOBT) or fecal immunochemical test (FIT) for patients who might be bleeding internally.
Overall, a digital rectal exam is only a preliminary step in determining whether you have colon cancer. As the test is limited to less than 10 percent of the colon wall, the test is not a keen indicator of colon polyps, colon pouches or pre-cancerous growths existing deeper inside the gastrointestinal (GI) tract. Oftentimes, regular screenings with colonoscopy, sigmoidoscopy or certain x-ray procedures may be ordered, even if a rectal exam produces negative results.
Reviewed 12/12/2011 by David M. Nolan, M.D.
Diplomate of the American Board of Internal Medicine, 2011
Currently a Fellow of Gastroenterology, at UCI 2011-2014