Digital Rectal Exam: Reliable Practice, or Will It Go the Way of the Dinosaur?
During a digital rectal exam, a doctor checks the lower rectum, pelvis, and lower belly for cancer and other problems. Lately, though, the DRE has been called into question.
In today’s age, the term “digital” may make you think electronic or photographic. But, alas, digital here refers to a finger, so a digital rectal exam (DRE) is an examination of your rectum with the physician’s gloved and lubricated index finger. Both men and women undergo a digital rectal exam, usually at their annual physical exam, once they turn 50. For those with a high risk for cancer, the exams may begin earlier.
A digital rectal exam is not painful, but it’s not comfortable, either. According to Cancer.net, you should tell your doctor if you have hemorrhoids or anal fissures, as a digital rectal exam may aggravate them. Fortunately, it doesn’t take the physician long to do a digital rectal exam—rarely more than a minute or two.
Your doctor may do a digital rectal exam more frequently if you are experiencing any problems, such as a change in bowel habits, bleeding or discharge, or urinary problems.
What a Digital Rectal Exam Is For
In a digital rectal exam, the physician will evaluate the anal sphincter strength, which is valuable in cases of fecal incontinence; check for internal hemorrhoids; and feel for nodules or masses. The digital rectal exam is not a colon-cancer test on its own because the exam is limited by the length of the physician’s finger reach. (See sidebar.)
For women, a digital rectal exam also allows the physician to feel for abnormalities in the area between the rectum and the vagina. Some physicians will press on the pelvic area while performing the digital rectal exam in order to palpate the ovaries and uterus. The woman’s position for a digital rectal exam is the same as for a pap smear—on her back, feet in the exam-table stirrups.
For men, the primary reason for a digital rectal exam is to palpate the prostate, which sits right in front of the rectum. The most common positions for the digital rectal exam: standing and bent over at the waist or lying on an exam table in the fetal position, knees pulled up. Apprehension about the digital rectal exam is a primary reason many men avoid wellness exams.
OCCULT BLOOD CHECK
At the time of your digital rectal exam, a small bit of stool may be obtained to test for blood, especially if you’re having any symptoms, like a change in your bowel habits. This test is called a fecal occult blood test—occult meaning blood that is not visible. A positive result means blood was found in the sample and further testing may be required to find the source of the blood, such as ulcers, polyps, hemorrhoids, or benign or cancerous tumors.
There are two different tests for occult blood: the guaiac test and the immunoassay test. The guaiac test has been around longer. Guaiac is a chemical that changes color when blood is detected. The immunoassay (or immunochemical test) uses a protein that binds to hemoglobin (blood).
The Centers for Medicare and Medicaid Services (CMS) says that the immunoassay test has “moderately better test performance characteristics” compared to the guaiac method.
The immunoassay test offers fewer false positives due to dietary elements, the reading is quantitative (vs. just positive or negative), and is believed to be more sensitive to picking up cancers. With both tests, certain medications, like aspirin and other blood thinners, can affect the test results.
Is The Male Digital Rectal Exam Worthwhile?
Some experts believe a blood test called the PSA (prostate-specific antigen) makes the digital rectal exam unnecessary for men. PSA is a protein that is often elevated in men with prostate cancer. However, in 2012, the U.S. Preventive Services Task Forces (USPSTF) recommended against routine PSA testing; it may lead to over-treatment of slow-growing, non-harmful tumors and unnecessarily risky prostate biopsies, according to the USPSTF. Our post “It Isn’t Time to Abandon the Prostate-Specific Antigen Test Just Yet” discusses the pros and cons.
The committee didn’t address the digital rectal exam. However, according to Ryan Terlecki, M.D., “The evidence suggests that in most cases, it is time to abandon the digital rectal exam.” Dr. Terlecki, a Wake Forest Baptist urologist, published an article on the topic in Current Medical Research and Opinion.
To reach his conclusion, Dr. Terlecki and his researchers reviewed records of 38,340 men who received an annual digital rectal exam and PSA test for three years. The subjects were followed for up to 13 years. Of particular interest were the 5,064 men who had a normal PSA test but an “abnormal” digital rectal exam. Only 2 percent of these men had clinically relevant prostate cancer.
“When PSA testing is used, the digital rectal exam rarely assists in diagnosing significant disease,” said Terlecki. “In cases where PSA testing is used, the digital rectal exam should be abandoned in common clinical practice.”
For related reading, see these posts:
Can Prostate Supplements Reduce Your Risk of Prostate Cancer? 
What Is Robotic Prostatectomy & The Advantages of Robotic Surgery 
What Can Skew a PSA Test? These 10 Factors Can Affect Your Numbers 
It may be uncomfortable, but a digital rectal exam doesn't take long.
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