Prostate Gland Biopsy

Prostate gland biopsy is the needle excision of a prostate tissue specimen for histologic examination. Indications include potentially malignant prostatic hypertrophy and prostatic nodules. Most prostate gland biopsies are performed using transrectal ultrasound guidance. Occasionally, a transurethral approach may be used if the transrectal approach is contraindicated.

Purpose

• To confirm prostate cancer
• To determine the cause of prostatic hyperplasia

Patient preparation

• Describe the procedure to the patient, answer his questions, and tell him that the test provides a tissue specimen for microscopic study.
• Tell him who will perform the biopsy and where.
• Make sure the patient or an appropriate family member has signed an informed consent form.
• Check the patient's history for hypersensitivity to the anesthetic or other drugs.
• For a transrectal approach, administer enemas until the return is clear and administer an antibacterial agent to minimize the risk of infection. This approach may be performed on outpatients without an anesthetic.
• Just before the biopsy, check vital signs and administer a sedative.
• Administer a prophylactic antibiotic, as ordered.
• Instruct the patient to remain still during the procedure and to follow instructions.

Procedure and posttest care

Transrectal approach

• Place the patient in the left lateral position.
• A digital rectal examination is performed before an ultrasound probe is inserted. A curved needle guide is attached to the finger palpating the rectum. The biopsy needle is pushed along the guide into the prostate that was localized by ultrasonography.
• As the needle enters the prostate, the patient may experience pain. Biopsies are obtained from the base, midgland, and apex on both sides of the prostate.
• If an abnormality in the rectum is identified, that area is localized by ultrasonography and a specimen is collected from there as well.
• The specimen is immediately placed in a labeled specimen bottle containing 10% formaldehyde solution.

Transurethral approach

• An endoscopic instrument is passed through the urethra, permitting direct viewing of the prostate and passage of a cutting loop.
• The loop is rotated to obtain tissue and then withdrawn.
• The specimen is placed immediately in a labeled specimen bottle containing 10% formaldehyde solution.

Both approaches

• Check vital signs immediately after the procedure, every 2 hours for 4 hours, and then every 4 hours.
• Observe the patient for signs and symptoms of hematoma and infection, such as redness, swelling, and pain. Watch for urine retention, urinary frequency, and hematuria.

Precautions

• Complications may include transient, painless hematuria and bleeding into the prostatic urethra and bladder.

Normal Findings

Normally, the prostate gland consists of a thin, fibrous capsule surrounding the stroma, which is made up of elastic, and connective tissues and smooth­muscle fibers. The epithelial glands found in these tissues and muscle fibers drain into the chief excreting ducts.

Abnormal findings

Histologic examination can confirm cancer. Further tests - bone scans, bone marrow biopsy, tests for prostate­specific antigen, and serum acid phosphatase and prostatic acid phosphatase determinations - identify the extent of the cancer. Acid phosphatase levels usually rise in metastatic prostatic carcinoma; they tend to be low in carcinoma that's confined to the prostatic capsule. In the latter case, radical surgery
and irradiation, although controversial, can provide a high cure rate. If discovery of cancer is delayed, treatment neccssitates estrogen therapy because tumor growth depends on testosterone secretion.

Histologic examination can also be used to detect benign prostatic hyperplasia, prostatitis, tuberculosis, lymphomas, and rectal or bladder cancer.

Interfering factors

• Patient's inability to follow instructions or to lie still
• Inadequate bowel preparation
• Failure to obtain an adequate tissue specimen
• Failure to place the specimen in formaldehyde