In prostate biopsy, a thin needle is used to extract tissue samples from the prostate gland; the specimens are sent to a laboratory for microscopic examination. Two techniques may be employed. In the majority of cases, an ultrasound probe is used to guide a needle through the rectum and into the prostate (transrectal approach). Rarely, a thin needle may be inserted through the perineum, the patch of skin located between the anus and scrotum, into the prostate (perineal approach). A biopsy is considered the only definitive way to confirm prostate cancer in men who have high PSA levels or a lump detected by a urologist during a digital rectal exam (DRE).
Purpose of the Prostate Biopsy
- To establish a diagnosis of prostate cancer
- To detect prostate disorders or enlarged prostate
- To detect an abnormal growth within the prostate
- To help diagnose the cause of infertility in a male
Who Performs It
- A urologist or a specially trained radiologist
- The perineal approach is considered less accurate, and is usually done only in cases where a prostate has a specific nodule or obvious diffuse abnormality.
- In some cases, prostate cancer may be diagnosed incidentally after a transurethral resection of the prostate (TURP), a surgical procedure to remove excess prostate tissue in men with benign prostate enlargement (known as benign prostatic hyperplasia, or BPH). In this procedure, the prostate is accessed with a thin viewing tube (resectoscope) that is passed through the urethra; a wire is passed through the instrument to remove excess prostate tissue, and samples are routinely sent to a laboratory for microscopic examination.
- In some cases, a biopsy may fail to detect cancer cells, resulting in a false-negative result. The more tissue specimens that are taken, the smaller the risk of missing cancer.
Before the Prostate Biopsy
- Before a transrectal biopsy, antibiotics will be prescribed to prevent infection.
- Your doctor may tell you to stop any blood thinners you are on for seven to 10 days prior to the biopsy.
- You may receive a cleansing enema 2 to 4 hours before a transrectal biopsy to clear your intestine and provide better visibility during the test.
- You will be asked to disrobe and put on a hospital gown.
- Just before the biopsy, you may be given a mild sedative to relax you.
What You Experience
- You are asked to lie on your side on a table. While you may feel some discomfort during the biopsy, anesthesia is not commonly used.
- A thin, cylindrical ultrasound probe may be gently inserted into your rectum. This device transmits an image of your prostate to a video screen, so the doctor can precisely guide needle insertion into the gland.
- To obtain the prostate specimens, the doctor may use a spring-loaded biopsy device to push a tiny needle through the wall of the rectum and into the prostate, and remove a small core of tissue. Alternatively, a thin biopsy guide is inserted into your rectum, and a long, thin needle is inserted through the guide and rotated to withdraw tissue (this method may cause pain as the specimens are obtained).
- The doctor typically extracts 6 to 12 specimens from various areas in the prostate for microscopic examination.
- The procedure takes about 10 to 15 minutes.
- You will be positioned on an examining table—either on your side; on your knees and chest with your arms outstretched before you; or on your back with your feet raised and resting in stirrups.
- The skin over the perineum is cleansed with an antiseptic, and a local anesthetic is injected to numb the area.
- The doctor gently inserts a finger into the rectum to immobilize the prostate.
- A thin needle is inserted through the perineum into the prostate, rotated to secure a sample, and withdrawn. Several more samples may be obtained by reinserting the needle at other angles.
- Pressure is placed on the puncture site until bleeding has stopped, and a small bandage is applied.
- The procedure usually takes less than 30 minutes.
Risks and Complications
- The most common aftereffects are soreness, temporary blood in the urine (hematuria), minor rectal bleeding, and blood in the semen. These effects are temporary and typically harmless.
- Rare but serious complications include excessive bleeding and infection.
After the Prostate Biopsy
- The biopsy site may remain sore for about 2 to 3 days. You may be given pain-relieving medication to allay any discomfort.
- You may be prescribed antibiotics after a transrectal biopsy to further reduce the risk of infection.
- Resume your normal activities when it is comfortable to do so.
- You should expect to see blood in your urine and stool for 2 to 3 days and in your semen for 2 to 4 weeks. This is harmless.
- Notify your doctor immediately if you develop a fever, persistent bleeding, or severe redness or swelling at the biopsy site.
- A pathologist inspects the tissue samples under a microscope for the presence of unusual cells. In most cases, a definitive diagnosis can be made and appropriate treatment will be initiated.
- If cancer is present, treatment decisions are based on the extent and aggressiveness of the cancer—as determined by your biopsy results, DRE, and PSA levels, and sometimes by additional tests such as a bone scan.
- If the biopsy is negative, a repeat biopsy may be necessary—especially when PSA levels are very high, have risen rapidly, the DRE is very suspicious for cancer, or the initial biopsy shows cells suspicious for cancer or a precancerous condition.
The Johns Hopkins Consumer Guide to Medical Tests
Simeon Margolis, M.D., Ph.D., Medical Editor
Updated by Remedy Health Media