- Digital rectal exams (DREs) may not be useful as a primary screening tool for detecting prostate cancer.
- A new study out of Germany, presented at the European Association of Urology Annual Congress in Milan, found that DREs may be missing prostate cancers in earlier stages, compared to other screening methods.
- Doctors recommend if a patient is screened for prostate cancer, prostate specific antigen (PSA) blood tests are used as the primary screening tool.
Using digital rectal examinations (DREs) as a primary screening tool for detecting prostate cancer may not be the most effective option, new research shows.
The news comes from a study out of Germany—which has not yet been published or peer-reviewed, but was presented in March at the European Association of Urology Annual Congress in Milan—in which researchers suggest that digital rectal exams may be missing many cancers in earlier stages.
“One of the main reasons for screening for prostate cancer is to detect it in patients as early as possible as this can lead to better outcomes from treatment,” lead study author Agne Krilaviciute, PhD, a researcher at the German Cancer Research Center, said in a news release. “But our study suggests that the DRE is simply not sensitive enough to detect those early stage cancers.”
Digital rectal exams are widely used by physicians to check for palpable signs of prostate cancer—a healthcare provider inserts a gloved, lubricated finger into the rectum to feel for any unusual swelling or lumps.
In some countries, like Germany, digital rectal exams are the sole method used in a national screening program for prostate cancer; in the states, the U.S. Preventive Services Task Force (USPSTF) does not recommend digital rectal exams for screenings due to a lack of evidence.
Because digital rectal exams may lack a certain sensitivity to diagnose prostate cancers in earlier stages, researcher are recommending that other methods, like prostate specific antigen (PSA) blood tests and magnetic resonance imaging (MRI), are instead to help screen for the disease. Here's what to know.
How Is Prostate Cancer Diagnosed?
Digital Rectal Exams Underperform as Prostate Cancer Screening Tools
For the study, researchers used data from the PROBASE trial, a German prostate cancer screening study across four different universities in Germany involving 46,495 men who were 45 years who were enrolled between 2014 and 2019.
The men were divided into two groups: Half were offered a PSA test immediately age age 45; the other half were offered a digital rectal exam with a delayed PSA blood test at age 50.
A total of 6,537 men in the delayed screening group underwent the digital rectal exam—only 57 were referred for follow-up biopsies due to abnormal findings, and just three were diagnosed with cancer, all with low-grade disease, according to senior study author Peter Albers, MD, professor of urology at Düsseldorf University.
Compared to prostate cancer detection rates of other screening options, like PSA, the rate of detection using digital rectal exams were substantially lower, researchers said, pointing to previous research that PSA testing at 45 years old can find four times more prostate cancers than digital rectal exams.
Ultimately, researchers concluded that widespread use of PSA and MRI would better serve as prostate cancer screening options than digital exams.
How Is Prostate Cancer Treated?
Why Aren't Digital Rectal Exams as Useful as Other Methods?
The theory behind digital rectal exams is relatively simple: Because the prostate sits on top of the rectum, and most prostate cancers grow in the part of the prostate closest to the rectum, they become palpable through the rectum according to Matthew Cooperberg, MD, MPH, professor of urology at the University of California, San Francisco.
But sometimes, the changes in tissue may not be pronounced enough to detect with a finger, or the cancer is in a part of the prostate that isn't easily reached through a digital exam. "A substantial minority of cancers develop further away from the rectum and cannot be felt, and others are high grade and dangerous well before they can be felt on DRE,” Dr. Cooperberg told Health.
And by the time prostate cancer is able to be felt through a digital rectal exam, it may signal later-stage disease—in that case, other methods may be useful in detecting prostate cancer earlier.
"Physical exam features often develop at more advanced stages of local disease, and as such, do not offer the same sensitivity as serum PSA testing in this setting," Rashid Sayyid, MD, MSc, Urologic Oncology Fellow of the Prostate Cancer Foundation, University of Toronto, told Health.
What Causes Prostate Cancer?
Current Prostate Cancer Screening Options and Guidelines in the U.S.
There are no specific guidelines currently in place for prostate cancer screenings. The U.S. Preventive Services Task Force (USPSTF) recommends that men ages 55 to 69 should make individual decisions about being screened for prostate cancer with a PSA test.
In making the decision, the agency says men should consider the benefits and harms of screening. Meanwhile, men over 70 should not be routinely screened for prostate cancer.
Other organizations—including the American Urological Association (AUA) and the American Cancer Society (ACS)—have similar recommendations.
In the U.S., when a person is screened for prostate cancer, “we rely heavily on PSA testing as part of prostate cancer screening, which has resulted in a significant decrease in prostate cancer mortality over the last 30 years,” Preston Sprenkle, MD, a urologic oncologist at Yale Medicine, told Health.
He added that the new study confirms the usefulness of PSA tests, and aims to move Germany's screening protocols away from using digital exams.
"This study is suggesting that Germany should rely more on blood tests like PSA and not just the digital rectal exam," Dr. Sprenkle said. "There is a fair bit of data in the U.S. as well that DRE has limited utility as a screening exam and most of our guidelines allow for it but do not specifically recommend its use alone for prostate cancer screening."
The other upside of using PSA tests for prostate cancer screening: It may open more men up to the idea.
“If the aim of a screening [program] is to pick up cancers as early as possible and the current screening tool isn’t doing that job, then that is a fundamental failure of that approach,” Dr. Albers said in the news release. “We speculate in our paper that not only is the DRE not useful for detecting cancer, but it may also be one reason why people don’t come to screening visits—the examination probably puts a lot of men off."