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The views expressed are those of the author and do not necessarily reflect the views of ASPA as an organization.
By Burden Lundgren
November 18, 2014
In my last column, I discussed some of the complex issues around prevention. Now I want to zero in on screening. Generally, a screening consists of tests used on a broad population (e.g., all women within a certain age range) to identify the early stage of a serious disease or to identify risk factors that may predispose to disease. The idea of screening has taken a hit over the past few years as the practices of mammography and prostate-specific antigen (PSA) testing came into question. However, most people love the idea of screening. The more things we can screen for, the better.
It is believed that screening keeps us safe. It’s the comfort food of medicine. But, like most comfort food, sometimes it’s really not that good for us. The underlying theory is that diseases caught at their earliest stages are more amenable to treatment. But, it’s not that simple.
In the middle of the night, I sat with women dying of breast cancer, agonizing over the thought that they had put off having a mammogram. They were blaming themselves for their own deaths. They needed someone to reassure them that, had they sought diagnosis earlier, the result might well be the same. In fact that might be true. Early diagnosis might or might not improve odds. It certainly doesn’t guarantee success.
Then there is the matter of cost and evidence. Many states run a panel of blood tests on every baby born in order to identify metabolic diseases. The tests are expensive and positive results are few. However, identifying babies with these conditions can prevent lifetime medical catastrophes for the affected infants.
For example, there is good evidence that screening colonoscopies can prevent colon cancer deaths (as well as some evidence that they are being done too often). For any test, successes and failures are measured over populations. There is no way to tell if an individual has or has not benefited from a screening test.
Skin cancer is serious. This year nearly 13,000 Americans will die from it. The physician assistant (PA) in my dermatologist’s office insists that I have annual skin examinations. But will an annual examination help?
My dermatologist agrees that there is no evidence that annual exams improve outcomes. More importantly, so does the United States Preventive Services Task Force. That means that there is no reason to believe that I will fare any better by having the PA examine me than if I had noticed something myself and brought it to her attention. But my insurance pays for screening, so why not?
Well, there is the fact that my insurance pays for it. Health insurance, both public and private, pays for scores of procedures with no evidence of effectiveness. Yet, at the same time we complain about health care costs. Certainly that should not be the case – but, beyond the costs, what is the problem?
We undergo screening tests to avoid risk. However, the tests themselves are not without risks. What is the risk of having a health care professional examine my skin for suspicious lesions? After all, there are no incisions, drugs or even blood tests involved.
As in all screening exams, it comes down to false positives and false negatives. If the PA finds a lesion deemed suspicious, a biopsy will be performed. The biopsy will incur costs and some risk (though very low in this case). If the biopsy is read as cancer, further therapeutic intervention may be necessary. There will be a possibility (but only that) that a life may have been saved. If the biopsy is negative, the process stops. It was a false positive.
But suppose the PA tells me that nothing was found to warrant further investigation. That’s good news – unless the PA is wrong (false negative). Will that reassurance mean I will be less likely to spot something on my own? After all, I’ve eaten the comfort food so everything must be all right.
Some question the age at which screening should begin. But perhaps a more pressing issue is when they should stop. Should we perform screening tests on 90-year-olds? How about people in their 80s? Or even their 70s? Absent the known diagnosis of a terminal condition, how does a physician tell a patient he will probably not survive long enough to benefit from a screening test? It’s an uncomfortable conversation and one too seldom had.
Clearly, public policies concerning screening tests need to be more science-based and some screening tests are valuable across populations. But what should we do as individuals?
First, give up the idea of comfort food. Screening is a risk/benefit situation. Know what both are. Having had a negative screening test does not absolve you from being alert to changes in your own body. If something doesn’t feel right, it probably isn’t.
But what if the test is positive? Sometimes there is a single answer, but, often a positive test is the first step on a long and complicated journey. It is your journey, and you are the only person who can decide which way to go. But, in the happy case that all turns out well, please do not say that the test saved your life. You do not know that. That’s just comfort food.