A digital rectal exam (DRE) is a widely used screening method to detect prostate cancer. However, results from the PROBASE trial suggest that DRE is not sensitive enough to detect this cancer in its early stage. These findings were presented on 9th March at the European Association of Urology Annual Congress in Italy.
Prostate cancer (PCa) is the most frequent cancer and the second leading cause of cancer death in men. Early detection may help to choose a more effective treatment and to inhibit progress to metastatic disease and death.1 Digital rectal exam (DRE) is widely used by medical professionals to check the prostate gland for unusual swelling or lumps in the rectum as an initial signs of PCa in men. In some countries, such as Germany, it is the sole method used in a national screening programme for the disease. However, new data from the PROBASE trial, coordinated at the German Cancer Research Centre in Heidelberg, suggest that this technique may be missing many cancers in their early stages.2
The PROBASE trial was a multicentre PCa screening study across four university sites in Germany. Between 2014 and 2019, this trial enrolled 46,495 men aged 45 years. Half of the participants were subjected to prostate-specific antigen-based (PSA) screening immediately at age 45 (immediate screening). The other half were offered digital rectal examination (DRE) with delayed PSA screening at age 50 (delayed screening). PSA tests were used to classify participants into a low (<1.5 ng/mL), intermediate (1.5-2.99 ng/mL) or high (≥3 ng/mL) risk group. In cases of confirmed PSA values ≥3 ng/mL, participants were recommended to perform a prostate biopsy.1
Of 23,301 participants who accepted baseline PSA testing in the immediate screening arm, 186 men (0.8%) fell into the high-risk group after repeated PSA measurements. Of these, 120 underwent a biopsy, and 48 were diagnosed with PCa. In the delayed screening arm, 23,194 participants were enrolled and 6,537 underwent a DRE. Of those, suspicious findings were found only in 57 patients, two of which two showed PCa (detection rate at 0.03%).1,2
This study shows that DRE is not an effective method for the early detection of PCa. In contrast, PSA testing appeared to be much more efficient, detecting four times more PCas than DRE at the age of 45. The researchers believe that one of the reasons why the DRE might be failing is that early-stage PCa may not have the size and stiffness to be palpable. Additionally, the doctors speculate that DRE is not only not useful for detecting cancer, but it may also be one reason why people do not come to screening visits. The researchers are now calling for the widespread use of PSA testing and MRI scans as part of screening programmes instead of DRE.2