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The truth about prostate cancer...
Around 1,500 new cases of malignant cancer of the prostate gland develop in Irish men throughout Ireland each year. It makes cancer of the prostate the second most common cancer in men, cancer of the skin being the most common.
On average some 720 deaths in Irish men are attributed to cancer of the prostate each year. This places cancer of the prostate second in the league table to lung cancer as the commonest causes of cancer death in Irish men. These stark statistics underline the fact that cancer of the prostate is a big cause of sickness and death in this country. Yet, we have no public health campaigns to either highlight the importance of the disease or to specifically inform the public about the screening, diagnosis and treatment of carcinoma of the prostate gland.
Screening for prostate cancer
In this article, I want to specifically deal with the subject of screening for prostate cancer but before doing so perhaps we should get down to basics and explain exactly where the prostate gland is located. I strongly suspect that if you asked a sample of Irish men where the prostate gland was, that you would receive a very diverse range of answers.
It would be a reasonable practice for men over the age fifty to attend their GPs at least once in order to be assessed for possible risk of prostate cancer.
The prostate gland is part of the male reproductive system. It is a doughnut shaped organ that is wrapped around the urethra, which is the tube that conveys urine out from the bladder and on through the penis. A normal sized gland is approximately the same size as a plum. If you can imagine the outflow from the bladder into the urethra as being like a funnel, the prostate nestles under the bladder just at the funnels neck. Therefore when the prostate enlarges it can compress the urethra and can also press up into the floor of the bladder thereby potentially interfering with the flow of urine from the bladder through the urethra.
Another important anatomical consideration is that it is possible to identify and feel the prostate gland through DRE (digital rectal examination). Put simply, the doctor can examine the gland by gently inserting a lubricated gloved index finger through the anus. The examining finger is then gently pushed up the rectum and the prostate is felt as a mass located to the front of the examining fingertip. The gland can be felt quite clearly through the wall of the rectum.
DRE is an essential step in the assessment of the prostate gland. The examining doctor can ascertain the size of the gland and whether it feels hard or relatively soft. It is also possible to detect hard lumps within the gland that would be suggestive of the possibility of cancer. However, DRE alone is no longer considered sufficient for the assessment of possible prostate cancer. It is now universally recommended that DRE be combined with a PSA (prostate specific antigen) test in order to establish if a risk of cancer exists.
It is important to emphasise that these two tests combined cannot diagnose if a man has prostate cancer. They simply suggest that further testing is needed in order to establish if cancer is present.
There is a fundamental difference between screening tests and diagnostic tests. Screening tests are designed to screen out those individuals who require further testing to confirm or exclude a particular diagnosis. Diagnostic tests will often involve obtaining tissue samples by biopsy that confirms if a cancer is present or not. The DRE and PSA are screening tests and even if the results are abnormal they are not diagnostic of cancer. This is a very important concept for people to grasp because many men experience great alarm and fear if their PSA result is elevated.
We have no public health campaigns to either highlight the importance of the disease, or to specifically inform the public about the screening, diagnosis and treatment of carcinoma of the prostate gland.
PSA is a protein that is produced within the duct system of the prostate gland. Normally the bulk of this protein is contained within the gland and blood levels of PSA tend to be low. However, if the architecture of the prostate gland is disturbed, increased levels of PSA escape into the general circulation giving rise to elevated levels of PSA in the blood. This can happen with various diseases of the prostate gland and not just cancer. For example, in the case of BPH (benign prostatic hypertrophy), which means non-cancerous enlargement of the prostate, the PSA can also be elevated. This can also happen with inflammation of the prostate or prostatitis to give it its medical name.
Various herbal compounds have also been noted to affect PSA levels. Saw palmetto (Serenoa repens), which is often recommended for 'prostate conditions', can affect PSA levels. So, it is important to mention to your doctor that you are using herbal remedies if you are undergoing PSA testing. Prostate biopsy and cystoscopy (examination of the bladder with an endoscope) also raise PSA levels therefore PSA estimation should be deferred for several weeks after such testing in order to avoid obtaining an artificially high level on blood testing.
As mentioned earlier an abnormal DRE or an elevated PSA may suggest the presence of prostate cancer but that diagnosis can only be confirmed by examining a sample of prostate tissue. In either of those two scenarios it is normal practice to refer the man to a urologist for a biopsy and further assessment.
The sample of prostate tissue can be obtained in a number of ways. The commonest method for obtaining a sample of prostate tissue is by transrectal biopsy. This involves the use of an ultrasound scan, which outlines the prostate gland and allows the doctor to visualise the gland while guiding the biopsy needle into the gland from the rectum.
No anaesthetic needed
This sounds like a gruesome ordeal for the uninitiated but it can be performed as an outpatient procedure without need for an anaesthetic. Although the insertion of the instrument through the anus may cause some pressure, the passing of the needle through the rectum into the prostate is painless because the wall of the rectum does not contain pain nerve fibres. There may be some blood in the stool, urine or semen for a number of days after the procedure but the volume tends to be small, self-limiting and of itself does not require specific treatment. It is very important to stress that an ultrasound scan alone is not sufficient to make the diagnosis. A tissue sample is required.
If a diagnosis of prostate cancer is made following microscopic examination of the biopsy sample the PSA may be of additional value to the doctor. For example, a high pre-treatment PSA level correlates well with risk of cancer spread beyond the capsule enveloping the prostate gland. If the level is even higher again this suggests the possibility that cancer cells have spread to the local lymph glands. Furthermore, if pre-treatment PSA levels are not excessively high in a person with prostate cancer then local treatment alone may be sufficient. In other words additional chemotherapy, hormone therapy or radiotherapy might not be necessary because the cancer has been diagnosed before it had time to spread beyond the prostate gland.
In the case of radical prostatectomy, which means total removal of the gland through the abdominal route, it would be expected that the PSA would not be detectable. In that scenario a recurrence of detectable PSA would suggest the possibility of a recurrence of disease. It is standard practice to monitor PSA levels on an ongoing basis when a man has been treated for prostate cancer in order to confirm that he remains disease free.
Screening for prostate cancer usually starts at the age of fifty. If a man has a history of prostate cancer affecting his father or a brother such screening should probably commence at a younger age. Some authorities suggest that screening in such cases should begin at forty but there is no universal agreement on this point. It has also recently emerged that if a female were diagnosed with breast cancer under the age of forty that this would also increase the risk of her first-degree male relatives developing prostate cancer.
DRE and the PSA test are not infallible tests and there is some ongoing controversy regarding their use and interpretation. Further research is clearly needed in this area to improve the precision of our screening and diagnostic tools. In the meantime it would be a reasonable practice for men over the age fifty to attend their GPs at least once in order to be assessed for possible risk of prostate cancer.
* Dr Leonard Condren is the medical editor of irishhealth.com.
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Last Reviewed: 7th February 2003