Ask the Pharmacist

Q) I just received news that my blood work came back showing that my PSA is high. What does that mean and what comes next for me?

A) The prostate is a walnut-shaped gland that is found only in males and is a part of our reproductive system. It is located just below the bladder and wraps around the urethra, the tube that transports urine from the bladder to the outside world.

The purpose of the prostate is to produce much of the fluid that makes up semen. Prostate cancer is the most common cancer found in males in Canada.

This year, roughly 24,000 Canadian men will be diagnosed with prostate cancer representing nearly 20% of all male cancer cases and 4,500 men will die from prostate cancer which makes up nearly 10% of all cancer deaths in males. While these numbers are sobering, much of the recent news regarding prostate cancer has been extremely positive.

Since a screening test known as the PSA was developed in the mid 1990’s, our ability to detect prostate cancer and intervene early has led to some remarkable improvements in treatment. Today, nearly 90% of prostate cancers are found while the disease is still confined to the gland and its surrounding tissues. When this is the case, nearly everyone can be expected to survive for at least five years. In fact, the death rate from prostate cancer had declined by more than 50% since the PSA test was first introduced.

However, as many of you may already be aware, the PSA is far from a perfect screening tool which has led to some controversy regarding its validity and use. PSA stands for prostate-specific antigen, a protein found within your blood that is produced only by the prostate. When there is a problem with the prostate, and at other times as well, it releases more of this protein which can serve as an early warning signal that something may be wrong with this gland.

While medicine does, and should, love early detection of diseases, the issue with the PSA test is that it very frequently is elevated for reasons unrelated to prostate cancer. This can lead to a risk for false positive results and the resultant psychological toll these cause, or worse, further investigations that come with their own possible adverse events. In fact, only about 1 in 4 abnormal PSA results is due to cancer. To make matters worse, not all prostate cancers elevate PSA so about 15% of these cancers cannot be detected using this simple blood test.

Higher than normal PSA levels (most labs define “normal” as 4ng/ml or lower) can be caused by:

· An enlarged prostate which is extremely common as we age into our 40’s and beyond
· An infection or inflammation of the prostate
· A bladder exam
· Sexual activity that includes ejaculation
· Riding a bicycle
· A recent medical test or procedure on the prostate
· Use of a urinary catheter
· Warmer climates

As such, there are strong arguments to be made as to whether a value higher than 4 should precipitate a biopsy, which is a more accurate but also more invasive procedure for identifying prostate cancer. In general, based on a PSA alone, a reading of less than 4 equates to about a 15% chance of prostate cancer, between 4 and 10 there is a 25% chance and, if the reading is above 10, there is a greater than 50% chance that cancer exists.

Usually, the first step upon discovering a high PSA is to order another PSA test (and sometimes more than one) sometime thereafter and to perform the dreaded digital rectal exam (i.e. the finger probe up your rectum to see if it “feels” abnormal) if it hasn’t been done already. The second PSA test will help give a better idea if further investigation is needed. It is normal for the PSA value to go up and down but elevated PSAs that are due to cancer tend to elevate much more quickly than those due to other causes.

If the PSA increases by more than 0.7 ng/ml in a year, there is an increased risk that cancer is the reason behind this steep rise. Other blood tests may also be helpful in determining whether a biopsy may be warranted. One such test that might be ordered is a comparison of the amount of free to bound PSA. Bound PSA means that it is attached to other proteins. Free-PSA levels are often higher in those with non-cancerous conditions of the prostate. A percent-free PSA above 25% is normal whereas a percentage below 18 to 12 (there is a debate as to what level should trigger genuine concern) often leads to a recommendation for a biopsy.

Another blood test that also might prove useful is one that measures PSA density. This compares the level of PSA in the blood in relation to the actual size of the prostate. A high PSA density (above 0.1) is more often related to a possibility of cancer. If a decision is eventually made to proceed with a biopsy, often an MRI is performed beforehand to identify areas of the prostate from which the tissue could be taken.

The most common method uses a trans-rectal ultrasound to guide a hollow needle to the specific areas on the prostate. The ultrasound (a thin flexible tube just larger than a pen with a tiny camera) is inserted into the rectum and moved into place near the prostate. Using the images from this, a spring loaded needle is then inserted into the rectum, guided to the prostate, and then used to extract several small samples of tissue from both sides of the prostate. The procedure takes about 30 minutes and generally uses local anaesthesia.

Risks from a prostate biopsy are minimal but could include infection (you will be given antibiotics both before and after the procedure to help prevent this), bleeding, trouble urinating and discomfort at the biopsy site. If the samples show cancerous cells, further tests will be done to determine how advanced the cancer is (known as its staging). If the biopsy turns up negative, this does not definitively exclude the possibility of cancer (i.e. the other tissues other than the ones sampled might have cancer) but it is still very good news.

Next steps would be to recheck your PSA in three to six months and, if it remains elevated, a second biopsy would usually be ordered. Though there is much to digest with various acronyms and numbers, we should focus on the positives. A high PSA result does not necessarily mean you have cancer and even if further tests should prove otherwise, modern medicine has improved in leaps and bounds with respect to our ability to effectively eradicate it in the majority of cases. For more information about this or any other health related questions, contact your pharmacist.