medical information

Prostate Biopsy | Description | Precautions | Aftercare | Purpose

Definition

Prostate biopsy is a surgical procedure to remove small samples of prostate tissue for microscopic examination. The prostate gland lies just below the urinary bladder and surrounds the urethra. The gland produces enzyme-rich secretions that contribute to the seminal fluid via ducts that enter the urethra.

Purpose

A prostate biopsy is usually performed to determine whether the patient has prostate cancer.Occasionally, it may also be used to diagnose a condition called benign prostatic hypertrophy (BPH), a progressive enlargement of the prostate that may cause obstruction of urine flow in older males.

A prostate biopsy is ordered when other tests have indicated a need to visualize samples of prostate tissue for abnormalities. These tests are the digital rectal examination (DRE) and theprostate-specific antigen (PSA) blood test. The DRE is a routine screening test performed by the physician to feel for any enlargement or nodular growth of the patient's prostate. Higher than normal levels of the protein marker PSA can be an indicator of prostate cancer. If either the DRE or PSA results are abnormal, the physician may order additional tests, including a prostate biopsy. Computed tomography scans, magnetic resonance imaging, and ultrasonograms provide detailed pictures of the prostate and can also be used to determine the extent and spread of prostate disease. However, a prostate biopsy (examination of the cells of the gland under a microscope ) remains the most definitive test for diagnosing and staging prostate cancer.

Precautions

A prostate biopsy is ordered only when the physician has used prior diagnostic tools that indicate an abnormal prostate. Prostate biopsies are usually performed by a urogenital system specialist (urologist). Special precautions will be required before the biopsy if the patient has a history of abnormal bleeding or is currently taking a blood-thinning medication.

Description

According to the American Cancer Society, next to skin cancer, prostate cancer continues to be the most commonly diagnosed cancer in American men. Prostate biopsies are usually performed in one of two ways. They can be performed by inserting a needle through the wall of the rectum or by inserting a needle through the perineum (the area between the base of the penis and the rectum). The patient may be given a sedative to help him relax. In preparation for the biopsy the patient will have an enema, and will begin antibiotic therapy to prevent an infection.

Needle biopsy via the rectum

This procedure, called a transrectal ultrasound-guided biopsy, is the most commonly performed type of prostate biopsy, and can usually be performed in the physician's office without general anesthesia. The patient is asked to lie on his side or on his back with his legs in stirrups. Local anesthetic is administered, and the urologist uses a thin needle attached to a spring-loaded gun directed by ultrasound to collect samples from the prostate. The gun is able to insert and remove the needle into the prostate tissue rapidly, creating less discomfort and trauma for the patient. The procedure can often be completed within 30 minutes. Usually the tissue samples are obtained by fine-needle aspiration, as opposed to larger core tissue samples that create more discomfort for the patient.

Needle biopsy via the perineum

If the chances of a complication for the patient are too great for the transrectal ultrasound-guided biopsy, the urologist may choose another route through the perineum for access to the prostate. The skin of the perineum is thoroughly cleansed and a local anesthetic is injected at the site where the biopsy is to be performed. Once the area is numb, the physician makes a small (1 in/2.5 cm) incision in the perineum. The physician places one finger in the rectum to guide the placement of the biopsy needle, and the needle is then inserted into the prostate. A small amount of tissue is collected, and the needle is withdrawn. The needle is then reinserted into another part of the prostate and another sample of tissue is collected. In this manner, samples are collected from several areas. After the procedure, pressure is applied at the biopsy site to stop bleeding. The patient usually experiences only slight discomfort and the procedure can often be completed within 30 minutes.

Preparation

Before scheduling the biopsy, the physician, nurse, or physician assistant completes a thorough medical history of the patient to include all medications that the patient is taking, a list of any medications to which the patient is allergic, and a history of any bleeding problems. The patient may be given an antibiotic shortly before the test to reduce the risk of infection. Usually an enema is required prior to the biopsy procedure, and the patient will be given instructions on administration of the enema.

Aftercare

The physician, nurse, or physician assistant should monitor the patient for any complications, excessive bleeding, or pain from the procedure. After the procedure, the patient commonly experiences minor rectal bleeding, blood in urine or feces, and sometimes blood in the semen. These side effects usually last only for a few days. Often, the physician will prescribe antibiotics to guard against potential infection. The patient should drink fluids to help reduce any burning sensation and the chances of a urinary tract infection.

Complications

Prostate biopsy performed with a bioptic gun is a low-risk procedure. The possible complications include abnormal bleeding, urinary tract infection, or an inability to urinate. These complications are treatable, and the patient should notify the physician promptly if symptoms occur. If the patient develops a high fever, chills, or unusual pain or bleeding after the procedure, he should notify the physician immediately.

Results

The prostate tissue is fixed, stained, and prepared on glass slides for microscopic analysis by a pathologist who will examine the samples for the presence of cancerous cells. If the prostate tissue samples show no sign of inflammation, and if no cancerous cells are detected, the results are normal. If malignant cells are present, the pathologist grades them, in order to estimate the aggressiveness of the tumor. The most commonly used grading system is called the Gleason system; the higher the Gleason score, the more likely it is that the cancer is fast-growing and may have already spread to other areas (metastasized).

Health care team roles

Training

The urologist and several non-physician health care providers are involved in the biopsy process. The urologist has received specialized training in ultrasound-guided biopsy procedures. The additional health care team members have obtained specialized training to assist the urologist by preparing the patient for the procedure and monitoring the patient during the procedure. They also ensure that the urologist has all of the instruments and equipment required before, during, and after the procedure. A health care provider properly packages and labels the specimens for transport to the pathology laboratory.

Patient education

The health care provider can be an important resource for patients who require a prostate biopsy. Health care professionals should make men aware of certain risk factors that can increase their chances of developing prostate cancer. Three important risk factors are age greater than 50, family history of prostate cancer, and African American descent. A health care provider should explain in detail the procedure to be performed and the possible complications associated with the biopsy.

The health care provider will instruct the patient in self-administering an enema. Following a needle biopsy, the health care providers should tell the patient that he may experience some minor discomfort, and that he should avoid strenuous activities for the remainder of the day. The health care provider should also inform that patient that he may notice a small amount of blood in his urine or minor bleeding from his rectum for two or three days after the test. The provider should emphasize to the patient that he or she should call the physician immediately when experiencing unusual bleeding, pain, fever, or an inability to urinate for 24 hours. The health care provider should provide the patient with the results of the test as soon as they are available.

KEY TERMS

Benign prostatic hypertrophy (BPH)— A noncancerous condition of the prostate that causes growth of the prostate tissue, thus enlarging the prostate and obstructing urination.

Biopsy— The surgical removal and microscopic examination of living tissue for diagnostic purposes.

Computed tomography (CT) scan— A medical procedure in which a series of x rays is taken at different angles and reconstructed by a computer in order to form detailed pictures of areas inside the body.

Digital rectal examination— A routine screening test that is used by physicians to detect any enlargement in the prostate gland or any hardening or other abnormality of the prostate tissue. The doctor inserts a gloved and lubricated finger (digit) into the patient's rectum, which lies just behind the prostate. Typically, since a majority of tumors develop in the posterior region of theprostate, they can be detected through the rectum.

Magnetic resonance imaging (MRI)— An imaging procedure that creates a detailed computer-constructed image of the target tissue based upon its deflection of a magnetic field produced by a powerful magnet. The magnetic field deflection is measured using radio waves (not x rays).

Pathologist— A doctor who specializes in the diagnosis of diseases by studying cells and tissues removed by biopsy.

Ultrasonogram— An image produced by high-frequency sound waves that cannot be heard by human ears. The sound waves are deflected by internal organs and tissues. These sound waves produce a pattern of echoes that are then used by the computer to create pictures of areas inside the body.

Resources

BOOKS

Berkow, Robert, ed. The Merck Manual of Diagnosis and Therapy. Rahway, NJ: Merck Research Laboratories, 2004.

Rakel, Robert E., and Edward T. Bope, eds. "Prostate Cancer." In Conn's Current Therapy 2001. Philadelphia: W. B. Saunders Company, 2001, pp. 754-756.

Scher, Howard I., et al. "Prostate Cancer." In Clinical Oncology, 2nd ed., edited by Martin D. Abeloff, et al. New York: Churchill Livingstone, 2000, pp. 1823-1884.