Digital rectal examination (DRE)
Annual digital rectal examination is recommended for patients aged over 45 years. The examination is included in the scope of services of the German statutory health insurance funds. Unusual DRE results are the second most common examination findings to entail prostate needle biopsy for the exclusion of a malignant prostate tumour (the most common reason is elevated serum PSA levels). The sensitivity of the rectal digital examination is limited, ranging well below 40%.
The digital rectal examination serves to assess the consistency, shape and size of the prostate, in addition to evaluating the mobility of the rectal mucosa. Findings that give reason to suspect the presence of a tumour (a lump that is not painful to touch) should always be confirmed by a transrectal ultrasound-guided prostate biopsy. However, the DRE is only capable of detecting tumours with a minimum volume of about 0.2 ml. This DRE, as an important pillar of early detection, is not without controversy. Its sensitivity strongly depends on the examiner’s experience and only the peripheral zone of the prostate near the rectum can be palpated. Moreover, more than two-thirds of all prostate carcinomas diagnosed by palpation have already grown into extraprostatic tissue.
Consequently, this examination method alone cannot be regarded as a sufficient diagnostic measure for the early detection of prostate cancer, but it remains an essential part of early prostate cancer detection and diagnosis. In about 30% of the cases where the DRE results are positive, a carcinoma is detected by means of needle biopsy.