The Digital Rectal Exam (DRE) is a simple, physical assessment used by a healthcare provider as a method of screening for potential abnormalities of the prostate gland. The prostate is a small, walnut-sized gland located deep within the male pelvis, situated just in front of the rectum. Because of its location, the DRE allows a physician to manually evaluate the gland’s physical status, which is otherwise inaccessible for routine examination. This procedure is performed to detect physical changes in the prostate that may suggest prostate cancer or other benign conditions.
The Digital Rectal Exam Procedure
The digital rectal exam is a brief, in-office procedure that requires no special preparation from the patient. A patient is typically asked to undress from the waist down and may be positioned either lying on their side with the knees drawn toward the chest or standing and bending over the examination table. This positioning allows the physician optimal access to the prostate gland through the wall of the rectum.
The physician first puts on a glove and applies a sterile, water-based lubricant to one finger. The lubricated index finger is then gently inserted into the rectum. The patient may experience a feeling of pressure or an urge to urinate as the finger is inserted and positioned to feel the prostate.
The examination usually takes less than a minute to complete. While some people may find the procedure uncomfortable or slightly embarrassing, it should not be painful. If significant pain occurs, it may suggest an underlying condition, such as inflammation of the prostate, known as prostatitis.
Physical Characteristics the Exam Identifies
During the digital rectal exam, the physician performs a tactile analysis of the prostate gland’s structure. The healthy prostate typically feels smooth, elastic, and symmetrical, similar in consistency to the tip of a nose. The physician systematically palpates the gland to assess its size, symmetry, and surface characteristics.
One common finding is a generalized enlargement of the gland, which often suggests Benign Prostatic Hyperplasia (BPH), a non-cancerous condition common in older men. In BPH, the prostate remains smooth but is significantly larger than its normal size.
A finding that raises suspicion for malignancy is the presence of hardened areas, lumps, or nodules on the surface of the prostate. Unlike the soft, symmetrical enlargement of BPH, prostate cancer often presents as a firm or rock-hard area, sometimes described as induration, which may be irregular or asymmetrical. Though the DRE can only assess the back surface of the gland, a palpable, suspicious nodule is sufficient grounds for further diagnostic investigation.
DRE’s Function Alongside Other Screening Methods
The digital rectal exam is rarely used as a standalone screening test for prostate cancer in current medical practice. Its effectiveness is maximized when it is used in conjunction with the Prostate-Specific Antigen (PSA) blood test. This combined approach is utilized because each test can detect abnormalities that the other might miss due to the prostate’s anatomical position.
A significant limitation of the DRE is that the physician can only physically feel the portion of the prostate gland closest to the rectum, which is the posterior surface. Any tumors located in the central or anterior areas of the gland may be missed by the exam. This is where the PSA blood test, which measures a protein released by prostate cells, serves as a complementary tool.
Conversely, a DRE can detect some cancers that do not cause a noticeable elevation in PSA levels. Studies have shown that prostate cancers detected solely by an abnormal DRE, despite a normal PSA reading, often possess features associated with aggressive tumors. Therefore, an abnormal DRE finding is often considered sufficient to warrant a referral for a biopsy, regardless of a normal PSA result.
When both the DRE is suspicious and the PSA level is elevated, the likelihood of prostate cancer is significantly increased. Suspicious findings from either the DRE or the PSA test do not confirm a cancer diagnosis, but they indicate the need for subsequent, more definitive diagnostic procedures. These typically involve advanced imaging, such as an MRI, followed by a prostate biopsy to confirm the presence of malignant cells.