Prostate Biopsy

By Dr Liji Thomas, MD.

The prostate is a small gland that wraps around the urethra, at the base of the urinary bladder. It produces semen, the fluid vehicle of spermatozoa. A biopsy of the prostate is a procedure in which a small sample of prostate tissue is removed in order to examine it, usually in search for signs of malignant transformation of prostate cells.

The procedure does not cause major pain, but the soreness in the rectal area may persist for some days after the procedure. In addition, there may be slight bleeding through the rectum or urethra, during the passage of stools, urine or semen. Antibiotics may be prescribed in order to prevent infection.

Types of prostate biopsy

A biopsy of the prostate is usually taken in one of three ways: as transrectal ultrasound-guided systematic (TRUS) prostate biopsy, as transurethral prostate biopsy or as transperineal prostate biopsy.

TRUS prostate biopsy is taken through the rectum; here an ultrasound probe is inserted into the rectum to visualize the prostate, and the biopsy is taken after anesthetizing the prostate - all under ultrasound guidance. In most cases, 10-18 samples are taken. TRUS biopsy is the optimal method to confirm the presence of cancer, and its grading, in most patients who are suspected of having prostate cancer.

Transurethral prostate biopsy is a biopsy that is taken through the urethra, under endoscopic guidance. Instruments are passed via the endoscope to remove several tissue samples. The patient is usually given general anesthesia during the procedure.

Transperineal prostate biopsy: in this case the patient is anesthetized, and a minor incision made in the perineum. Through it, a needle is inserted to remove samples of prostate tissue.

Indications

In most cases, prostate cancer is asymptomatic until it becomes locally advanced or metastatic. A prostate biopsy is therefore performed:

When the prostate is enlarged, and produces symptoms
When an asymptomatic prostatic nodule is detected during routine digital rectal examination
When there is other suspicion of prostate cancer, such as a high prostate-specific antigen (PSA) level

Normal biopsy results usually lower the chances of prostate cancer. However, finding abnormal cells on the biopsy does not always mean prostate cancer is present. If cancer cells are found, the biopsy result is said to be positive.

Furthermore, a Gleason score (which varies with the type and grade of malignant change) will be assigned by the pathologist. This is based on the characteristics of the cancer cells. The score may lie between 2 and 10. The lower the score, the less aggressive the cancer is likely to be. This will help the healthcare provider to predict the rate of growth, and to choose the type of treatment that is most appropriate.

If atypical, but non-cancerous cells are seen, the doctor helps to decide on the steps that should be taken to reduce the risk of cancerous change. In some cases, the patient may be advised to have the biopsy repeated.