If a digital rectal exam, an elevated PSA level, or both cause your doctor to suspect that you might have prostate cancer, the next step is usually a biopsy of the prostate (prostatic biopsy). A biopsy is the removal of tissue, so it can be analysed microscopically, at the level of cells.

A prostatic biopsy (a biopsy of prostate gland tissue) is accomplished today in a fairly minor procedure. A device that incorporates both an ultrasound probe and a mechanism that delivers biopsy needles (often called a biopsy gun) is inserted into the rectum. The transrectal ultrasound (TRUS) portion of the device allows the physician to position the biopsy gun next to any suspicious areas of the prostate. The "gun" portion then deploys a small disposable needle that removes a sample of prostate tissue measuring 0.4 mm wide and about 12 to 15 mm long. This sample of tissue is called a core.

If early prostate cancer is suspected, cancer that is too small to feel or to see using the TRUS probe, the doctor will probably take more than one sample (core). The standard procedure in this situation used to be to divide the prostate into six parts and to take six cores-one from each area. Some research suggests that taking more samples than six is optimal, so, frequently, 8 to 14 cores are now biopsied. The more tissue removed, the more thorough and accurate the results. However, taking more samples also increases the chance of discomfort and side effects.

View an animation of a prostate biopsy from the Prostate Centre.

WHAT TO EXPECT
Your doctor will ask you to stop taking any blood thinners such as coumadin, plavix, or aspirin (ASA) for about a week before the prostate biopsy. Be sure to indicate what vitamins or other supplements you might be taking, as these can also thin the blood and inhibit clotting. (Many doctors recommend stopping intake of Vitamin E before a prostate biopsy, for example.) You should consult your physician before resuming consumption of any blood thinning agents.

Because of the risk of infection, you will also be asked to take antibiotics both before and after the biopsy. Antibiotics are necessary because the biopsy is performed through the rectum, so infection is a concern. You should follow directions carefully and finish the course of antibiotics prescribed.

You may need to use a laxative or to have an enema before the biopsy to clear stools out of the rectum. Sometimes, enemas are performed in the clinic or hospital about two hours before the procedure. More likely, you will be asked to use a fleet enema, which you can purchase without prescription at your local pharmacy.

Usually, you are allowed to have a normal meal before the biopsy. Also, the biopsy is usually done under local rather than general anaesthetic. Infrequently, a doctor may recommend a general anaesthetic when a large number of cores will be taken.

During the biopsy, you will lie on your side in the foetal position with your knees drawn up towards your chest. You should feel no lasting pain, just the same discomfort that you might feel getting an injection. The biopsy itself takes about twenty to thirty minutes, but you may be asked to set aside a morning or and afternoon. You will definitely need to stay in the hospital or clinic for a while after the procedure, so health professionals can monitor your reaction to the biopsy.

Most men can resume most of their normal activities on the same day as the procedure, although your doctor will probably recommend that you refrain from vigorous exercise or physical activities that put pressure on the prostate (for example, cycling or horse riding). A few doctors also counsel men to abstain from sex for a few days, as orgasms do cause the prostate to contract. Most, however, now place no restrictions on diet or sexual activity after the procedure. In any case, your body will likely tell you when the region has healed sufficiently for you to resume all your normal activities comfortably. Until that time, if you experience soreness, you can take Tylenol, not aspirin, for relief.

SIDE EFFECTS
It is normal to experience soreness in your rectum and penis after a prostatic biopsy. This usually goes away in a few hours. Minor bleeding from the rectum is also common for a day or so. About half of the men who undergo this procedure also notice blood in their urine or sperm. Usually, this minor bleeding stops inside of a week, but it can last up to 6 weeks.

It is also normal for a prostatic biopsy to cause an elevated PSA level because of the inflammation in the biopsy sites. This rise in prostate-specific antigen in the blood does not signal either the presence of cancer or a rapid growth of cancer; it is a reaction to the biopsy.

Uncommon and potentially dangerous side effect include the following:

• Extensive bleeding from the rectum: Very rarely, a biopsy needle nicks a small artery in the rectum, and bleeding will be more severe than normal. Alert your physician to this situation, as you may require a blood transfusion and some procedures to stop the bleeding.
• Infection: Infection is the main risk of a biopsy of the prostate. About one man in 50 develops an infection, but, usually, these infections are minor and easily treated with antibiotics. If you develop a fever shortly after a prostatic biopsy, you should consult your doctor or go to your local emergency ward.

BIOPSY RESULTS
A pathologist will examine the tissue samples to determine whether the samples show cancer; the result will usually be either positive or negative for cancer. Sometimes, however, you might get a report that reads neither positive nor negative but "suspicious" or "atypical." This result means that the cells do not look cancerous, but neither do they look normal. These "atypical" cells might be either low or high grade prostatic intraepithelial neoplasm, better known as PIN.

Prostatic intraepithelial neoplasia: Low grade PIN, also called mild dysplasia, is not cancer and may not necessarily lead to cancer. These cells are very slightly abnormal, and they are not invasive. High grade PIN, although not cancer because not invasive, is more worrying. It is often called a pre-cancer or a precursor for cancer because approximately half of the men diagnosed with high grade PIN receive a diagnosis of prostate cancer over the next 5 years. However, having high grade PIN does not mean you will inevitably get prostate cancer. High grade PIN cells look like cancer cells. The only difference is that they are not invasive. The prostate contains many tiny spherical glands that drain into the urethra through ducts. These spheres have a wall that is two-cell layers thick, and they are covered on the outside by a membrane called the basement membrane. The diagnosis of high grade PIN means that cancerous-looking cells were found on the inside of these spherical glands, but these cells have not broken out of the basement membrane-they have not invaded other areas. Because there is no invasion by these cells into the surrounding tissue, high grade PIN is sometimes referred to as carcinoma in situ (cancer cells remaining in place).


Normal prostate cells (A) form regular glands with walls intact. When prostate cancer cells (B) form and multiply, the glands are irregularly shaped and there are clumps of oddly shaped cells in the stroma (between glands).

If cancer is present, biopsy results will also include an analysis of that cancer. At the very least, they will name the type of cancer and how abnormal the cancer cells are. This last result, the extent of the cancerous cells' abnormality, is expressed as a numerical grade. Depending upon the various other findings and the biopsy results, you may also be given preliminary information about the stage of the cancer. (Staging is the medical profession's best educated guess about whether cancer has spread, and accurate staging usually requires more tests.) See information on the clinical staging and grading of prostate cancer.

Positive/Negative: In the case of prostate cancer, a positive response is bad news. If the biopsy report is positive, it means the pathologist has found cancerous cells in the tissue samples. Negative means no cancer was found in any of the samples. Note: It is possible for a biopsy to miss cancer. Estimates are that any biopsy detects about 75 per cent of existing cancers. When you consider the amount of tissue sampled in relation to the area of the prostate, this finding is easier to understand. So, if signs and symptoms of prostate cancer persist after a pathologist determines that there is no cancer in your biopsy samples, your doctor will probably recommend another biopsy.

Type of cancer: Almost all prostate cancers (about 98 per cent) are adenocarcinomas. These cancers begin in the epithelial cells that cover or line the prostate. Most of these cancers begin in the peripheral zone of the prostate. Approximately 15 to 20 per cent begin in the central zone, and 10 to 15 per cent begin in the transitional zone. The biopsy report should also indicate the area of the prostate in which cancerous cells were found.

Ductal carcinoma is simply adenocarcinoma that began in or invaded the ducts of the prostate. Because this adenocarcinoma has a distinct appearance, and is often aggressive, a biopsy report might refer to it.

Transitional cell carcinoma is another possibility, though very rare. This cancer begins in the cells lining the prostatic urethra, the place where the urethra runs through the prostate. Only about 4 per cent of all cases diagnosed are of this type.

Neuro-endocrine carcinoma, also called small-cell cancer, is extremely rare too. This cancer begins in specialized epithelial cells whose exact function is not known. It grows quickly and metastasises early.