What is Screening?

by | Nov 10, 2015 | General Health

We hear a lot about “screening” for certain diseases. So, what is screening? We screen for diseases for which there is “high risk” in certain population groups. These diseases may be genetically transmitted, or found within certain age, social groups and sexes, or in certain environments where disease transmission is likely. What most people (even doctors) don’t fully appreciate is that the chief aim of screening is to reduce the impact of these diseases on society. It is a public health and cost-effectiveness issue more than it is a personal health one. The decision to screen consists of automatic recommendations based upon demographics, genetic, age, and sex characteristics. That is not to say that health care professionals and public policy makers do not also wish to protect individuals from the ravages of these same diseases.

Those of us who are old enough to remember have images in our memories of those American Lung Association vans that traveled around doing chest x-rays on everyone. They were looking for tuberculosis. TB was a highly publicized disease in my childhood, and it seemed logical to the medical authorities to go hunting to catch the disease early and get on with treatment. It was, after all, in the public interest to reduce the costs of treating and curing this debilitating and deadly disease.

It was not too many years later that those who studied the numbers figured out that the cost of all that screening far exceeded the cost of only doing x-rays on those who were suspected of having the disease, and treating those diagnosed. Screening did not make sense from an economic point of view. “Cost effectiveness” is the watchword for “screening” of any kind.

Screening is presented to us doctors as a mandatory part of the practice of good medicine. That is, we the medical community are taught to try to impose our medical will on our patients (or document the patient’s “non-compliance” if they refuse). We order patients to get their pap smears, or mammograms, or prostate exams, or colonoscopies, etc, just because she is a woman over 40, or he is a man over 50, etc. The academic data supports the “cost-effectiveness” of this approach (and the lawyers are lined up to sue those doctors whose patients died from a disease and the doctor didn’t prove he tried to screen).

It is interesting to know that some fairly large studies of screening (in the study I’m referring to, mammograms) while showing a 20% reduction in breast cancer deaths in the mammogram group vs the non-screened study group (especially in the 50-59 age group), did not show in any difference in “all cause” mortality between the two groups.

This brings up an interesting practical (and philosophical) decision. If you are a woman of fifty and want to be less likely to die of breast cancer by age 60, get screened. But you’re not any less likely to die during that same time frame; it’ll just be something else that gets you.

Have a nice day.