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Prostate biopsy is a surgical procedure that involves removing a small piece of prostate tissue for microscopic examination.
This test is usually done to determine whether the patient has prostate cancer. Occasionally, it may also be used to diagnose a condition called benign prostatic hyperplasia that causes enlargement of the prostate. In the United States, prostate cancer is the most common cancer among men over 50, and is the second leading cause of cancer deaths. According to statistics released in 2003, African American men in the United States are at much greater risk of developing prostate cancer after age 50 than Caucasian or Asian American men.
Prostate biopsy is recommended when a digital rectal examination (a routine screening test for prostate diseases) reveals a lump or some other abnormality in the prostate. In addition, if blood tests reveal that the levels of certain markers, such as PSA, are above normal, the doctor may order a biopsy.
The prostate gland is one of the three male sex glands and lies just below the urinary bladder, in the area behind the penis and in front of the rectum. It secretes semen, the liquid portion of the ejaculate. The urethra carries the urine from the urinary bladder and the semen from the sex glands to the outside of the body.
Prostate biopsies can be performed in three different ways. They can be performed by inserting a needle through the perineum (the area between the base of the penis and the rectum), by inserting a needle through the wall of the rectum, or by cytoscopy. Before the procedure is performed, the patient may be given a sedative to help him relax. Patients undergoing cytoscopy may be given either general anesthesia or local anesthesia. The doctor will ask the patient to have an enema before carrying out the biopsy. The patient is also given antibiotics to prevent any possible infection.
Needle biopsy via the perineum
The patient lies either on one side or on his back with his knees up. The skin of the perineum is thoroughly cleansed with an iodine solution. A local anesthetic is injected at the site where the biopsy is performed. Once the area is numb, the doctor makes a small (1 in) incision in the perineum. The doctor places one finger in the rectum to guide the placement of the needle. The needle is then inserted into the prostate, a small amount of tissue is collected, and the needle is withdrawn. The needle is then re-inserted into another part of the prostate. Tissue may be taken from several areas. Pressure is then applied at the biopsy site to stop the bleeding. The procedure generally takes 15-30 minutes and is usually done in a physician's office or in a hospital operating room. Although it sounds painful, it typically causes only slight discomfort.
Needle biopsy via the rectum
This procedure is also done in the physician's office or in the hospital operating room, and is usually done without any anesthetic, although some doctors prefer to inject a local anesthetic, usually lidocaine. The patient is asked to lie on his side or on his back with his legs in stirrups. The doctor attaches a curved needle guide to his finger and then inserts the finger into the rectum. After firmly placing the needle guide in the rectum, the biopsy needle is pushed along the guide, through the wall of the rectum and into the prostate. The needle is rotated gently, prostate tissue samples are collected and the needle withdrawn. When an ultrasound probe is used to guide the needle, the procedure is called a transrectal ultrasound-guided biopsy, or TRUS.
For this procedure, the patient is given either a general or a local anesthetic. An instrument called a cytoscope (a thin-lighted tube with telescopic lenses) is passed through the urethra. By looking through the cytoscope, the doctor can see if there is any blockage in the urethra and remove it. Tissue samples from the urinary bladder or the prostate can be collected for microscopic examination.
This test is generally performed in an operating room or in a physician's office. An hour before the procedure, the patient is given a sedative to help him relax. An intravenous (IV) line will be placed in a vein in the arm to give medications and fluids if necessary. The patient is asked to lie on a special table with his knees apart and stirrups are used to support his feet and thighs. The genital area is cleansed with an antiseptic solution. If general anesthesia is being used, the patient is given the medication through the IV tube or inhaled gases or both. If a local anesthetic is being used, the anesthetic solution is gently instilled into the urethra.
After the area is numb, a cytoscope is inserted into the urethra and slowly pushed into the prostate. Tiny forceps or scissors are inserted through the cytoscope to collect small pieces of tissue that are used for biopsy. The cytoscope is then withdrawn. The entire procedure may take 30-45 minutes. Sometimes a catheter (tube) is left in the urinary bladder to help the urine drain out, until the swelling in the urethra has subsided.
Many different tests can be performed to diagnose prostate diseases and cancer. A routine screening test called digital rectal examination (DRE) can identify any lumps or abnormality with the prostate. Blood tests that measure the levels of certain protein markers, such as PSA, can indicate the presence of prostate cancer cells. X rays and other imaging techniques (such as computed tomography scans, magnetic resonance imaging, and ultrasonograms), where detailed pictures of areas inside the body are put together by a computer, can also be used to determine the extent and spread of the disease. However, a prostate biopsy and examination of the cells under a microscope remains the most definitive test for diagnosing and grading prostate cancer.
Before scheduling the biopsy, the doctor should be made aware of all the medications that the patient is taking, if the patient is allergic to any medication, and if he has any bleeding problems. The patient may be given an antibiotic shortly before the test to reduce the risk of any infection afterwards. If the biopsy is done through the perineum, there are no special preparations. If it is being done through the rectum, the patient is asked to take an enema and is instructed on how to do it.
If a cytoscopy is being performed, the patient is asked to sign a consent form. The patient is also asked to take antibiotics before and for several days after the test to prevent infection due to insertion of the instruments. If a general anesthetic is going to be used, food and liquids will be restricted for at least eight hours before the test.
Following a needle biopsy, the patient may experience some pain and discomfort. He should avoid strenuous activities for the rest of the day. He may also notice some blood in his urine for two to three days after the test and some amount of rectal bleeding. If there is persistent bleeding, pain, or fever, and if the patient is unable to urinate for 24 hours, the doctor should be notified immediately.
When a cytoscopy is performed under a local anesthetic, the patient is asked to lie down for 30 minutes after the test and is then allowed to go. If general anesthesia is used, the patient is taken to the recovery room and kept there until he wakes up and is able to walk. He is allowed food and liquids after he wakes up. After general anesthesia, the patient may experience some tiredness and aching of the muscles throughout the body. If local anesthesia was administered, there is a brief burning sensation and a strong urge to urinate when the cytoscope is removed.
After the procedure, it is common to experience frequent urination with a burning sensation for a few days. Drinking a lot of fluids will help reduce the burning sensation and the chances of an infection. There may also be some blood in the urine. However, if blood clots are seen, or if the patient is unable to pass urine eight hours after the cytoscopy, the doctor should be notified. In addition, if the patient develops a high fever, and complains of chills or abdominal pain after the procedure, he should see the doctor right away. Although serious infections are rare, a few patients develop such severe illnesses as meningitis following a prostate biopsy.
Prostate biopsy performed with a needle is a low-risk procedure. The possible complications include some bleeding into the urethra, bleeding from the rectum, an infection, a temporarily lowered sperm count, or an inability to urinate. These complications are treatable and the doctor should be notified of them.
Cytoscopy is generally a very safe procedure. The most common complication is an inability to urinate due to a swelling of the urethra. A catheter (tube) may have to be inserted to help drain out the urine. If there is an infection after the procedure, antibiotics are given to treat it. In very rare instances, the urethra or the urinary bladder may be perforated because of the insertion of the instrument. If this complication occurs, surgery may be needed to repair the damage.
If the prostate tissue samples show no sign of inflammation, and if no cancerous cells are detected, the results are normal.
Analysis of the prostate tissue under the microscope reveals any abnormalities. In addition, the presence of cancerous cells can be detected. If a tumor is present, the pathologist "grades" the tumor, in order to estimate how aggressive the tumor is. The most commonly used grading system is called the "Gleason system."
Normal prostate tissue has certain characteristic features that the cancerous tissue lacks. In the Gleason system, prostate cancers are graded by how closely they resemble normal prostate tissue. The system assigns a grade ranging from 1 to 5. The grades assigned to two areas of cancer are added up for a combined score that is between 2 and 10. A score between 2 and 4 is called low and implies that the cancer is a slow-growing one. A Gleason score of 8 to 10 is high and indicates that the cancer is aggressive. The higher the Gleason score, the more likely it is that the cancer is fast-growing and may have already grown out of the prostate and spread to other areas (metastasized).
Benign prostatic hyperplasia (BPH) — A noncancerous condition of the prostate that causes overgrowth 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 are taken and put together by a computer in order to form detailed pictures of areas inside the body.
Digital rectal examination — A routine screening test that is used to detect any lumps 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 the prostate, they can be detected through the rectum.
Magnetic resonance imaging (MRI) — A medical procedure used for diagnostic purposes where pictures of areas inside the body are created using a magnet linked to a computer.
Pathologist — A doctor who specializes in the diagnosis of disease by studying cells and tissues under a microscope.
Ultrasonogram — A procedure in which high-frequency sound waves that cannot be heard by human ears are bounced off internal organs and tissues. These sound waves produce a pattern of echoes that are then used by the computer to create sonograms or pictures of areas inside the body.
Urethra — The tube that carries the urine from the urinary bladder and (in males) the semen from the sex glands to the outside of the body.
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American Cancer Society. 1599 Clifton Rd., NE, Atlanta, GA 30329-4251. (800) 227-2345. http://www.cancer.org.
American Urologic Association. 1120 N. Charles St., Baltimore, MD 21201. (410) 223-4310.
National Prostate Cancer Coalition. 1300 19th Street NW, Suite 400, Washington, DC 20036. (202) 842-3600 ext. 214.
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Gale Encyclopedia of Medicine. Copyright 2008 The Gale Group, Inc. All rights reserved.
prostate biopsyA 'needle' biopsy of the prostate of older ♂ with either clinical–eg, ↑ firmness of prostate on rectal examination, or lab–eg, ↑ PSA findings commonly associated with prostate CA Approaches Perineal, transurethral, transrectal. See Digital rectal examination, Gleason's grade, Ploidy analysis, Prostate cancer, Prostate-specific antigen.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.