What is the significance of a normal digital rectal examination (DRE) of the prostate?

From the Guidelines

A normal digital rectal examination (DRE) of the prostate does not rule out the presence of prostate cancer, and its significance should be considered in the context of other screening tools, such as the prostate-specific antigen (PSA) test, and individual patient risk factors. The DRE is a brief procedure where a healthcare provider inserts a lubricated, gloved finger into the rectum to feel the prostate gland through the rectal wall, checking for abnormalities in size, shape, and consistency 1. While the DRE can detect prostate abnormalities, including enlargement or suspicious nodules, its sensitivity and specificity are dependent on the examiner, and considerable variability can occur with this test 1.

Key Points to Consider

• The DRE is often performed alongside a PSA blood test for more comprehensive screening, and men should discuss with their healthcare provider the appropriate frequency for prostate exams based on their individual risk factors and medical history.
• The American College of Physicians recommends that clinicians inform men between the age of 50 and 69 years about the limited potential benefits and substantial harms of screening for prostate cancer, and base the decision to screen on the risk for prostate cancer, a discussion of the benefits and harms of screening, the patient's general health and life expectancy, and patient preferences 1.
• The evidence is mixed on whether DRE is beneficial alone or in combination with PSA screening, and the USPSTF does not recommend screening with the PSA test, but suggests that men who opt to be screened should only do so after being fully informed of the benefits and harms 1.
• The harms of prostate cancer screening are substantial and include false alarms, overdiagnosis, high false-negative rates, anxiety, and discomfort, and the benefits of screening may not outweigh the harms for most men 1.

Recommendations

• Men should not rely solely on a normal DRE result to determine their risk of prostate cancer, and should discuss their individual risk factors and screening options with their healthcare provider.
• Clinicians should help men understand the potential benefits of early detection, the strengths and weaknesses of the various screening tests, and the risks of treating cancer that is detected by screening 1.
• Asymptomatic men older than 75 years or those who have a life expectancy less than 10 years should not be offered prostate cancer screening, due to the substantial harms associated with prostate cancer screening and treatment relative to questionable benefits 1.

From the FDA Drug Label

1. 2 Increased Risk of High-Grade Prostate Cancer Men aged 55 and over with a normal digital rectal examination and PSA ≤3.0 ng/mL at baseline taking finasteride 5 mg/day in the 7-year Prostate Cancer Prevention Trial (PCPT) had an increased risk of Gleason score 8 to 10 prostate cancer (finasteride 1.8% vs placebo 1.1%). The PCPT trial was a 7-year randomized, double-blind, placebo-controlled trial that enrolled 18,882 men ≥55 years of age with a normal digital rectal examination and a PSA ≤3. 0 ng/mL.

A normal digital rectal examination (DRE) of the prostate does not rule out the possibility of high-grade prostate cancer. In fact, men with a normal DRE and PSA ≤3.0 ng/mL at baseline who took finasteride 5 mg/day had an increased risk of Gleason score 8 to 10 prostate cancer compared to those taking placebo 2. This suggests that a normal DRE should not be relied upon as the sole means of detecting prostate cancer, and other diagnostic tools such as PSA testing and biopsy should be used in conjunction with DRE to assess the risk of prostate cancer.

From the Research

Significance of a Normal Digital Rectal Examination (DRE) of the Prostate

• A normal DRE does not necessarily rule out the presence of prostate cancer, as some studies have shown that a significant proportion of men with prostate cancer may have a normal DRE 3, 4.
• The sensitivity and specificity of DRE in diagnosing prostate cancer have been reported to be 81% and 40%, respectively, with a positive predictive value of 42% 3.
• However, the diagnostic accuracy of DRE can be influenced by various factors, including the experience of the examiner and the quality of the examination 5, 6.
• Some studies have suggested that DRE may be more useful in detecting prostate cancer in certain populations, such as those with elevated PSA levels or those with a family history of prostate cancer 6, 7.

Implications of a Normal DRE

• A normal DRE should not be relied upon as the sole means of ruling out prostate cancer, and other diagnostic tests, such as PSA and MRI, should be considered in conjunction with DRE 5, 6.
• The presence of a normal DRE does not necessarily mean that a patient is at low risk for prostate cancer, and other risk factors, such as age and family history, should be taken into account 4, 7.
• Further research is needed to fully understand the significance of a normal DRE in the diagnosis and management of prostate cancer 3, 5, 6.

Comparison with Other Diagnostic Tests

• DRE has been compared to other diagnostic tests, such as PSA and MRI, in terms of its diagnostic accuracy and utility in detecting prostate cancer 5, 6.
• Some studies have suggested that DRE may be more useful than PSA in detecting certain types of prostate cancer, such as high-grade disease 3, 7.
• However, other studies have suggested that MRI may be more accurate than DRE in detecting prostate cancer, particularly in patients with elevated PSA levels 5, 6.