Digital Rectal Examination

• What is a Digital Rectal Examination? (DRE)
• What is prostate cancer?
• Incidence of prostate cancer
• Performance of a DRE
• Examination findings in DRE
• What is a PSA Test?
• Screening for prostate cancer

What is a Digital Rectal Examination? (DRE)

A digital rectal examination (DRE) is an important element of a clinical examination, performed by a doctor or nurse. It is a direct examination of the rectum and nearby organs, including the anal canal, prostate and bladder. While it can be uncomfortable, a DRE is critical to identifying illnesses such as benign prostatic hyperplasia (BPH), prostatitis (infection of the prostate), haemorrhoids, anal fissures, prostate cancer and anal and rectal cancers. If these diseases are identified early, curative treatments may be possible, particularly in certain types of cancer.

Individuals with anal symptoms (such as itching, pain or bleeding), gastrointestinal symptoms (such as persistent diarrhoea, constipation, rectal bleeding), genitourinary symptoms (such as difficulty passing urine or a weak stream) or other relevant symptoms (such as prolonged back pain) should all have a DRE performed as part of a thorough clinical examination.

A DRE is an essential element of screening for prostate cancer, a very common cancer in men.

For more information about the male sex organs, see Male Reproductive System.

What is prostate cancer?

The prostate is a gland found only in men, sitting at the base of the bladder surrounding the urethra. It produces prostatic fluid, a component of the male ejaculate. In prostate diseases (such as BPH or prostate cancer), changes in the prostate tissue can press on the urethra and cause alterations to urinary function such as poor urinary flow, dribbling and a weaker stream.

Abnormal growth of the cells of the prostate can give rise to prostate cancer, 95% of which is of the type that affects cells lining the walls of the prostate (adenocarcinoma of the prostate). Rarely, neuroendocrine carcinoma of the prostate (cancer of the cells in the prostate that receive nerve signals and in response produce hormones) can develop, either as a primary tumour or within an established adenocarcinoma due to tumour cell differentiation. In many cases, prostate cancer is very slow-growing and never extends outside of the prostate. It is more common for men to die with prostate cancer rather than from it.

For more information about prostate cancer, see Prostate Cancer Types.

Incidence of prostate cancer

Prostate cancer is the fifth most common cancer in the world. Australia has one of the highest incidences of prostate cancer (105 cases per 100,000 males). To age 85, 1 in 4 Australian men will be diagnosed with prostate cancer and 1 in 25 will die from it, making it the second leading cause of cancer death in Australia. Although prostate cancer is the second most common cause of cancer in Aboriginal Australian males (after lung cancer), the incidence rate is lower in Indigenous men than in non-Indigenous men although exactly why this is so remains unclear.

Performance of a DRE

While a DRE can be an uncomfortable examination, the doctor or nurse will thoroughly explain the procedure so you know what to expect. Multiple positions can be used in the performance of a DRE; however, the easiest is often with the person being examined lying on their left side and the knees bent towards the chest. The full examination takes less than a few minutes and requires the individual to assist the examiner by relaxing and bearing down (as if straining at stool) as requested.

Examination findings in a DRE

A DRE allows the clinician to make a thorough examination of the anus, anal canal, rectum and nearby organs (such as the prostate). It allows the identification and diagnosis of a wide range of conditions, such as:

• Haemorrhoids or “piles”;
• Anal fissures (cracks in the skin at the anal margin);
• Anal and rectal cancer;
• Abdominal and pelvic infections; and
• Prostate disease, such as prostate cancer, BPH, prostate infections or prostatic cysts.

In prostate cancer, the normally rubbery and smooth prostate can feel hard and nodular, with loss of the middle groove separating the two lobes of the prostate.

What is PSA testing?

Prostate specific antigen (PSA) is a protein found in the blood that is produced by the cells of the prostate gland. A raised PSA is found in a range of prostate disorders that can all cause it to produce more PSA, which can then be detected through a simple blood test.

PSA testing is commonly used together with a DRE in testing for prostate cancer. PSA has been shown to be elevated 5–10 years prior to prostate cancer becoming symptomatic, allowing early diagnosis and curative treatment. As a screening test for prostate cancer of well men, DRE and PSA should both be performed.

While PSA testing has revolutionised the diagnosis of prostate cancer, it is not a perfect test. Men with elevated PSA do not necessarily have prostate cancer, and a few men with prostate cancer will not have an elevated PSA. Other prostate conditions (such as BPH and prostatitis) can increase the PSA, as well as some medications (such as the 5-alpha-reductase inhibitors and androgen receptor blockers). There is also some controversy surrounding how the level of PSA correlates to disease progression, mortality and quality of life.

For more information about prostate specific antigen testing, see Prostate Specific Antigen (PSA) Testing.

Screening for prostate cancer

Australia has the highest incidence of prostate cancer in the world and 1 in 25 Australian men will die from it. While a common disease, many prostate cancers are very slow-growing and may never cause clinical symptoms or spread outside the prostate. Most men with prostate cancer will die of something else.

A lot of controversy surrounds the use of DRE and PSA for routine screening for prostate cancer. There is not sufficient evidence to recommend routine screening of all men with no symptoms. While early diagnosis of prostate cancer is advantageous, several large studies have not shown that screening improves overall mortality from prostate cancer. This is largely due to the fact that many men have slow-growing, localised prostate cancer that is unlikely to spread or cause further problems. Diagnosing slow-growing disease often leads to investigations, treatment and psychological stress that may have been unnecessary and can themselves cause side-effects or additional harm. Research is now focused on how to identify men who would most benefit from treatment for early prostate cancer.

Guidelines recommend that your doctor should discuss the risks and benefits of prostate cancer screening with you based on your particular risk factors, so you can make an informed decision. For low risk men, screening is generally offered at age 50. If they have additional risk factors for prostate cancer (such as being African-American or having a strong family history of prostate cancer) screening tests may commence at age 40–45. At the appropriate age, your doctor should discuss with you:

• The natural history of prostate cancer (how the disease progresses over time and the symptoms and complications it may cause);
• The meaning of a positive or negative test on DRE and PSA, as well as  “false-positives” and “false-negatives” (that is, when the test reports a positive result but the individual does not have the disease, or a negative result when the individual does have the disease);
• Further tests and treatment options, in the event of a positive or negative result; and
• Risks, benefits and complications of treatments for prostate cancer.

If an individual elects for prostate cancer screening, a history and physical examination (including a DRE) will be initially performed. A simple blood test will allow a PSA level to be determined, and then further discussions between you and your doctor can take place depending on those findings.

In the event of an abnormality on DRE or an abnormally high PSA score, your doctor may refer you to a specialist for further investigation. The reference test for prostate cancer that is considered to be the most reliable is taking a biopsy of the suspicious area under local anaesthetic. This is usually done through the rectum under the guidance of ultrasound (Trans-rectal ultrasound-guided or “TRUS” biopsy). This will allow a pathologist to examine the prostate tissue and determine the presence and progression of any prostate cancer.

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