A common method for detecting prostate cancer may not be accurate enough as a reliable screening tool on its own, scientists warn.
The digital rectal examination (DRE) is widely used by medical professionals to check the prostate with a finger for swelling or unusual lumps in the rectum as an initial check for signs of prostate cancer in the men. men.
In some countries, such as Germany, it is the only method used in a national disease detection program.
But new research by scientists from the PROBASE trial coordinated at the German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ) in Heidelberg suggests that the technique may be missing many cancers in their early stages.
The findings, being presented at the European Urological Association Annual Congress in Milan, could have implications for the early detection of prostate cancer, the researchers say. Instead, they call for other testing methods to be used in routine screening.
“One of the main reasons for prostate cancer screening is to detect it in patients as early as possible, as this can lead to better treatment outcomes,” said Dr. Agne Krilaviciute, DKFZ researcher and lead author of the study. “But our study suggests that the DRE is simply not sensitive enough to detect these early-stage cancers.”
The PROBASE trial is a multicenter German prostate cancer screening study at four university sites (TU Munich, Hannover, Heidelberg, Düsseldorf) and involves 46,495 men aged 45 years who enrolled between 2014 and 2019. Since then, the men have had follow-ups to evaluate their health in the years after the screening. Half of the trial participants were offered prostate-specific antigen (PSA) blood testing immediately at age 45, while the other half were initially offered DRE with delayed PSA screening at age 50.
Finally, 6537 men in the late detection group underwent DRE and only 57 of these men were referred for follow-up biopsy due to suspicious findings. Only three were found to have cancer.
When compared to the detection rate using other methods, such as a PSA test, the detection rate using DRE was substantially lower , says Dr. Krilaviciute.
“The DRE was giving a negative result in 99% of cases and even those that were considered suspicious had a low detection rate,” says Dr. Krilaviciute. “The results we have seen from the PROBASE trial show that PSA testing at age 45 detected four times as many prostate cancers .”
Researchers believe that one reason DRE may be failing to detect cancers, particularly in young men, is because changes in prostate tissue may be too slight to detect with a finger. Additionally, some cancers occur in a part of the prostate that cannot be easily reached with a finger.
“Early-stage cancer may not have the size and stiffness to be palpable,” said Professor Peter Albers, a urologist at the University of Düsseldorf and lead author of the study.
"A separate analysis that used MRIs before biopsies to locate cancers in the prostate showed that about 80% of these were in an area that should be easy to reach with a finger and yet the cancers were not detectable by DRE ".
Researchers now call for widespread use of PSA testing and MRIs as part of screening programs instead of DRE.
“If the goal of a screening program is to detect cancers as early as possible and the current screening tool is not doing that job, then that is a fundamental failure of that approach,” Professor Albers said. “We speculated in our article that not only is the DRE not useful in detecting cancer, but it may also be one of the reasons why people do not attend screening visits; the exam probably turns off many men.
“In Germany, for example, the participation rate is less than 20% in the screening program for men aged 45 to 50 years. “If we offered PSA testing instead, more of them might be willing to come.”
