DIGITAL RECTAL EXAM
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Purpose: The digital rectal examination (DRE) has long been used for the diagnosis of prostatic disorders including prostate cancer, benign prostatic hyperplasia, and prostatitis. Abnormal findings include nodules, asymmetry, induration, and/or inflammation. The DRE can detect tumors in the posterior and lateral aspects of the prostate gland. An inherent limitation of the exam is that only 85 percent of cancers arise peripherally where they can be detected with a finger examination. T1 cancers are non-palpable.
No controlled studies have shown a reduction in the morbidity or mortality of prostate cancer when detected by DRE. The majority of cancers detected by digital examination alone are clinically or pathologically advanced. Therefore, the greatest value of DRE may be its use in combination with PSA testing. Recommendations: American cancer society recommends that the PSA blood test and the DRE be offered annually, beginning at age 50, to men who have a life expectancy of at least 10 years and to younger men at higher risk.
Procedure
- Advise patient that a finger needs to be inserted into the rectum in order to examine the prostate gland.
- Ask the patient to stand feet apart, face the examination table, and bend forward so that the arms or elbows are on the table. Other possible positions include the patient lying on his side with his knees pulled up to the chest (lateral Sims position) or in a knee-chest position while kneeling on the examination table.
- Next, spread the patient’s buttocks and examine the anal orifice.
- Before inserting a finger, tell the patient that he will feel a little pressure.
- Using lubricating jelly and a surgical glove, press the forefinger gently against the anus, then insert it into the rectum in a downwards angle toward the umbilicus, noting the sphincter tone.
- Wait a few seconds for the external sphincter muscle to relax.
- Palpate the prostate anteriorly, feeling both lateral lobes and median sulcus or raphe.
- Rotate the finger clockwise and counterclockwise 180 degrees to palpate the rectal mucosa.
- Note the size, consistency, tenderness, and presence of nodules.
- While the patient strains downward, withdraw the finger.
- Give the patient tissues for wiping.
- If stool is present on the glove, note the color, and, if necessary, perform a test for occult blood.
Normal prostate:
Size of a walnut (20 grams)
Rubbery
Nontender
Smooth
Symmetric
Abnormalities – Face trick:
Feel of forehead = normal prostate
Feel of nose = nodule = cancer
Feel of cheeks = bogginess/inflammation = prostatitis
Test performance: Urologists have been found to have relatively low inter-rater agreement for detecting prostate abnormalities. No data is available for DRE test performance characteristics in primary care.
Approximately 2 to 3 percent of men 50 years or older who undergo a single DRE have induration, marked asymmetry, or nodularity of the prostate.
Sensitivity and specificity: A meta-analysis of DRE in primary care screening for prostate cancer estimated a sensitivity for detecting prostate cancer of 59 percent and a specificity of 94 percent.
Positive predictive value: A meta-analysis of DRE in primary care screening for prostate cancer calculated an overall positive predictive value of 28 percent
.
Ways to improve the DRE in primary care settings (advice from practicing Northwestern urologists):
- Always use Lots of Lube.
- Always make sure the patient is positioned correctly with the elbows on the table.
- Be systematic – always use the same approach to make sure all areas of the prostate are evaluated.
- Practice using a digital rectal exam simulator to gain a better appreciation for anatomy.
Combining DRE and PSA: A multi-center screening study of 6630 men reported a cancer detection rate of 3.2 percent for DRE, 4.6 percent for PSA, and 5.8 percent for the two methods combined Abnormalities on DRE appear less likely to be from cancer if the PSA concentration is below 1.0 ng/mL than if the PSA concentration is between 3.0 to 4.0 ng/mL.
Other uses of the exam:
- For the diagnosis of rectal tumors and other forms of cancer.
- For the estimation of the tonicity of the anal sphincter which may be useful in cases of fecal incontinence or neurological diseases.
- In females, the DRE can be used for gynecological palpations of internal organs.
- For examination of the hardness and color of feces (ie. in cases of constipation and fecal impaction).
- Can be combined with the fecal occult blood test, which may be useful for diagnosing the etiology of anemia and/or confirming a gastrointestinal bleed.
References:
1. Epstein, JI. Pathology of prostatic neoplasia. In: Campbell's Urology, 8th ed, Walsh, PC (Ed), Saunders, Philadelphia 2002.
2. Krahn, MD, Mahoney, JE, Eckman, MH, et al. Screening for prostate cancer. A decision analytic view. JAMA 1994; 272:773.
3. Chodak, GW, Keller, P, Schoenberg, HW. Assessment of screening for prostate cancer using the digital rectal examination. J Urol 1989; 141:1136.
4. Smith, DS, Catalona, WJ. Interexaminer variability of digital rectal examination in detecting prostate cancer. Urology 1995; 45:70.
5. Hoogendam, A, Buntinx, F, de Vet, HC. The diagnostic value of digital rectal examination in primary care screening for prostate cancer: a meta-analysis. Fam Pract 1999; 16:621.
6. Catalona, WJ, Richie, JP, Ahmann, FR, et al. Comparison of digital rectal examination and serum prostate specific antigen in the early detection of prostate cancer: results of a multicenter clinical trial of 6,630 men. J Urol 1994; 151:1283.
7. Gerber GS, Brendler CB. Evaluation of the Urologic Patient: History, Physical Examination, And Urinalysis. In: Campbell's Urology, 8th ed, Walsh, PC (Ed), Saunders, Philadelphia 2002.
8. Yamamoto T, Ito K, Ohi M, Kubota Y. Diagnostic significance of digital rectal examination and transrectal ultrasonography in men with prostate-specific antigen levels of 4 NG/ML or less. Urology 2001; 58:994.
Category: Surgery Notes
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