By Dr. Christopher Morse, MD
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Well, we’re halfway through another Movember – the month where men of all ages work on their “mo’s” (moustaches) to help raise awareness and money for prostate cancer research. Since its inception in 2004 in Australia and New Zealand the campaign has become increasingly popular in a growing number of countries on every continent hitting Canada in 2007.
As a G.P. I can think of very few illnesses as misunderstood as prostate CA (docs will typically abbreviate cancer this way) and the screening for this malignancy is the centre of great controversy. Given that a recent study found that about one third of Canadians thought that women could contract prostate CA (a stat that is as astonishing as it is embarrassing – so much for Bio-30) a brief introduction may be worthwhile:
The prostate is a walnut-sized gland that sits just beneath the bladder in men through which the urethra travels. Its primary function is the production of seminal fluid. For the record – women do not have prostates.
There’s no question that prostate CA is a big deal. It is the most prevalent malignancy in men and the third leading cause of cancer death in men behind lung and colon. Doctors can screen for prostate CA – that is, look for it before there are any signs or symptoms – by digital rectal exam (or DRE, the finger-up–the-bum-test) and a blood test called the Prostate Specific Antigen (or PSA).
The problem is that screening for prostate CA doesn’t work very well. Several studies have shown that a man’s risk of dying from prostate CA remains essentially unchanged whether he undergoes screening or not. The bottom line is that if it’s going to get you – there’s often not a lot that anybody can do about it. To most people this statement is hard to believe. However there are a few compelling facts that indicate that not only is prostate CA screening unhelpful, but it may actually lead to harm.
There are many reasons why screening programs are largely unsuccessful – factors relating not only to the illness itself but also to the shortcomings of the tests.
As stated prostate CA is very common. The risk really starts in a man’s 40’s but it starts to become much more common after the age of 60. Its incidence continues to increase there after throughout the remainder of a man’s life. Prostate CA in younger men (that is, less than 60 years old) tends to be a more aggressive illness (to be blunt it often kills you faster). The problem that this creates for screening is partly that of timing. The more rapidly the cancer develops and progresses the easier it is to miss during periodic exams. It is quite possible that a man may have a negative screen at his routine physical, but may develop an advanced and incurable form of the illness before his next check-up. In this case the screening process clearly fails.
I have also stated that the incidence of prostate CA increases (and dramatically so) as a man ages. However the good news is that the older he gets the less and less likely the cancer will actually kill him. That is, even though the risk of prostate CA continues to increase, the likelihood that he will die from that cancer actually decreases. This is because the older a man is at diagnosis the more indolent the course of the disease tends to be.
The implication this has for screening is that large numbers of aging men will be found to have prostate CA who may then receive treatment that they do not need (as ultimately the cancer which was discovered if left alone wouldn’t have killed them anyway). The treatment for prostate CA – surgery, radiation, chemotherapy, and hormones – can be effective but can also significantly decrease the quality of a man’s life (incontinence and impotence are just two that come to mind).
Studies have found that roughly half of 80-year-old men who die of a non-prostate cancer related problem will have evidence of prostate CA on autopsy. Many of these men were not even aware that they had prostate cancer during their lives. Given what we know about the slow progression of the disease in older men it is reasonable to assume that these gentlemen would have had prostate CA for many years before their eventual deaths. If any of them had been screening during this time it would be safe to say that they would have tested positive and possibly been subjected to treatments which would have almost certainly decreased the quality of their lives to treat an illness would ultimately not have killed them anyway.
The reasons explained above are enough to make some men forego the prostate check, but unfortunately there is another major problem with screening – that which is a function of the test not the disease.
Both the DRE and the PSA can be quite inaccurate. The DRE can certainly be falsely negative (that is, can miss cancer that is present) or falsely positive (i.e. the gland feels abnormal when there is no cancer). But the real problem stems from the PSA. There are in fact many relatively trivial conditions that can lead to an elevated level of PSA and this results in a large number of false positives.
Any man with an abnormal PSA will likely undergo further investigation to determine if cancer is or is not present. At times a man will require a biopsy of the gland to help sort this out, and unfortunately this is not without risk.
I have a gent in my practice that wanted to be checked for prostate CA. After explaining all of the limitations and risks of testing he elected to have a PSA, which came back abnormal. After a referral to a urologist he was relieved that his biopsy came back as a normal prostate with no sign of cancer. However his biopsy lead to local infection – a well-documented, uncommon, and unavoidable risk of the procedure – with subsequent sepsis and several days in ICU. Luckily he didn’t die, but given the severity of his condition he very well could have. If he had I would have killed him by ordering the PSA. This type of adverse event happens only rarely, but it is something that every man should consider before blindly signing up for this test.
After reviewing this information with my male patients the next question they have for me is almost always – “Well doc, if we don’t screen for prostate cancer, how do we make sure that it doesn’t get me?” The unfortunate answer is nothing – there is no sure-fire way of insuring that a man does not contract and ultimately die from prostate cancer – not the news anybody really wants to hear.
In my general practice I try very hard to educate my patients about the pros and cons of prostate CA screening and do offer it to men still willing to go ahead with it. Obviously the best-case scenario (other than never developing the illness) is: We test, we detect, and we cure with no side effects – everybody feels good. The worst-case is: We test, we find an abnormality, and we investigate further only to discover it was a false positive – but kill the patient in the process. Usually the result is somewhere in between these two examples.
A recent article in the New England Journal of Medicine found that doctors need to screen 1055 men and treat 37 to prevent one prostate CA death over 11 years. Given all of the nasty things that are involved with treatment I’m not convinced that is worth it.
The Canadian Task Force on Preventive Health Care does not support routine screening for prostate cancer. The U.S. Preventive Services Task Force actually recommends against the practice.
The bottom line for now is:
- The decision as to screening for prostate CA or not is a very personal one which must be made on an individual basis.
- Give generously to the greasy-looking guys with their moustaches this and every Movember so that research can increase our knowledge about this important illness.