The procedure gives the physician-examiner access to the posterior portion of the prostate. Palpation allows assessment of size, tenderness, lumps, hardness, and other abnormalities that indicate cancer. Public awareness campaigns promote screening for prostate cancer, including the DRE, for men over 50. And DRE has been a routine part of a complete physical examination. The American Cancer Society promotes DRE as part of early detection of prostate cancer as well.
However, when the DRE has been studied in light of the evidence of validity and effectiveness, its clinical value has come to be questioned. As long ago as 1995, a study assessed inter-examiner agreement on DRE among urologists and found only “fair” agreement. Different experts performing the DRE on the same patient came to different conclusions from the exam.
A clinical study over 15 years ago looked at men who had prostate cancer that had been confirmed by a biopsy. They then underwent DRE by 2 experienced urology consultants. The study found no correlation between rectal examination findings and the presence of cancer. Cancer was present in men with a “normal” DRE and many who were cancer free had “abnormal” DRE findings.
More recently, a systematic review and meta-analysis published in 2018 found almost no support in the medical literature for the DRE. Sensitivity of DRE performed by primary care clinicians was 0.51. Sensitivity is the ability of a test to detect disease correctly. Sensitivity of .51 is basically a 50:50 chance of finding cancer. Specificity, which is the ability to correctly identify men who are cancer-free was 0.59. This means that nearly ½ of men with “normal” DRE had cancer. Positive and negative predictive values (PPV and NPV) were similarly disappointing. PPV was 0.41, meaning only about 40% of men with abnormal DRE had cancer. NPV was 0.64 showing almost 2/3 of men with a “normal” DRE actually had cancer.
Closer inspection of DRE’s effect on outcomes that really matter, i.e. death from prostate cancer, show little value. Having a DRE performed does not improve a man’s chances of dying from prostate cancer. Medical and chiropractic schools still teach the procedure and DRE continues to be performed in clinical practice. But the evidence shown by these dismal results in controlled trials have caused a gradual shift in clinical recommendations.
What this means for your patients, whether or not you actually perform the test, is that informed clinical decision making is critical in deciding about DRE. Providing information about DRE may assist your patients in making this decision.