We should aggressively screen for cancers early… right?
How can the idea of early detection and screening for cancers even be a debate? What could possibly be the downside of catching cancers early, and treating them before they cause great harm, even death? Logic says if you can’t prevent a cancer in the first place, then diagnose it as early as you can, and get it out of you! Right?
The answer may surprise you.
Contrary to what most of us believe, overdiagnosis and overtreatment of many cancers is a considerable threat to the health and well being of many.
You have probably read or heard recently that expert groups are now recommending against much of the currently routine prostate cancer screening via PSA. The same experts also issued controversial guidelines in 2009 regarding breast cancer screening.
These actions have understandably confused the public and inflamed patients and advocates. And it doesn’t stop at breast and prostate cancers. Sober second thought about all cancer screening will become more and more common as we ask tough questions.
Prostate Cancer and PSA Screening: One Example
There is no doubt whatsoever that the PSA test detects prostate cancers. But the test is prone to false negatives (not detecting a cancer that is really there) and also very prone to false positives (alarming a patient to a possible prostate cancer that is not really there).
So what is the harm of some false positives? Better to be safe than sorry, right?
Not if the false positive leads to an action that is more harmful than the disease itself! Prostate biopsies are very unpleasant, and often result in lasting side effects. Treatments for prostate cancer can lead to many serious consequences – not the least of which is impotence and/or incontinence, and other conditions that can severely and negatively affect a man’s quality of life.
Yet we know that the majority of prostate cancers develop late in life, are very slow growing and will never otherwise impair the health of the man harboring the cancer. The vast majority of men will develop prostate cancer in their lifetime without them ever knowing it, and will die WITH prostate cancer, but not FROM prostate cancer. Detecting a prostate cancer in these men may seem like a prudent course of action, but if they don’t know it’s there, and they will never suffer a day from it, then what is the value of detecting it in the first place, especially if that leads to a course of action that does harm or creates more problems than it solves?
So, Why Can’t We Stop Ourselves?
Many argue persuasively that despite the PSA test’s failings, it is the best we have right now, so let’s continue to use it, but do so more wisely. Doctors and patients, they say, should enter into more fulsome dialogues and have more shared decision-making so that patients are much better informed of the benefits and risks, and decide on a case-by-case basis whether PSA testing is right each individual.
This all sounds logical but if we are to educate men in this way, this dialogue MUST happen long before a blood sample is ever drawn. In my view, once there is a positive PSA test on the table, all bets are off – in effect the genie is now out of the bottle and it won’t easily be put back in.
Why is it too late at that time to debate the pros and cons of further investigation and/or treatment, as opposed to just leaving the cancer alone?
Two simple words – “cancer” and “fear”. Despite great strides in treating and curing many cancers, the very word “cancer” still conjures up a fear like no other. The very thought, for most people, of knowing a cancer is growing inside you swamps out your ability to ignore it, even if all evidence says that it will do you no harm.
If a cardiologist tells you that you have a mild heart murmur, you likely will not quake in fear or demand heart valve surgery. You probably will easily ignore it as long as it remains asymptomatic.
But if an oncologist tells you that you have a cancer, your first thought is likely to be “Oh my God, I’m going to die” and the second is likely “How do we get rid of it?”
Ignoring it because it won’t do you harm is just not in most people’s psyche, even if it all evidence says that is what you ought to do…
And so, I would argue that if you can’t put the genie back in the bottle after a PSA test comes back positive, think twice before you uncork the bottle in the first place.
I have no doubt that every prostate cancer survivor who had a PSA test is 100% convinced that he is alive today because of that test. And in some cases, that is no doubt true. But I’m also sure that he never stops to ask whether he was “cured” of something totally unnecessarily because it was never going to harm him in the first place. And yet he risked much, and it may indeed have cost him much (in pain, suffering and reduced quality of life) despite the fact that there was no good medical reason.
And so, the fear of cancer, perhaps more than any other factor, may be driving screening and treatment decisions at the individual level, and no doubt policy decisions at the societal level. We are getting there, but until we can take the fear out of a cancer diagnosis, I think this genie of overdiagnosis and overtreatment will never be able to be put fully back into the bottle, and all the logic, facts, data and evidence to the contrary will not prevail.
And the people who are harmed by all these good intentions may perhaps become bigger victims than those with cancers that are, and indeed ought to be, just left alone.
Michael A. Wosnick is a retired cancer researcher who blogs at Cancer Research 101. This guest post was adapted from Cancers: To Screen; Perchance to Treat? (June 6, 2010) and Screening for Prostate Cancer – PSA Testing or Not? (May 22, 2010). Follow Michael on Twitter @MichaelWosnick