Taking advantage of incidental findings

Have you ever gone looking for one thing and found another?

Maybe it's that favorite pen you find under the couch cushion when you're searching for your keys. Or perhaps you stumble across the leftover cheesecake in the fridge while looking for a healthier snack. Running across something you weren't actually looking for can be distracting — but it can also be a lucky break.

Did I mention the cheesecake?

A new study has pointed out that, at least in the world of medicine, serendipity of this sort can actually be lifesaving.

Can mammography screen for heart disease?

Researchers publishing in the Journal of the American College of Cardiology: Cardiovascular Imaging report a fascinating link between incidental findings on mammograms and heart disease. Ordinarily, mammograms screen for breast cancer by detecting tiny bits of calcium in breast tissue. These "microcalcifications" can be a telltale sign of breast cancer. But blood vessels can also have calcium deposits, and that can be a sign of atherosclerosis, the "hardening of the arteries" linked to heart attacks and strokes. Currently, a radiologist reading a mammogram might see blood vessel calcium deposits but make no mention of them because they are "incidental" findings — that is, they were not what the test was designed to detect and their meaning isn't clear. That could be about to change.

In this study, researchers compared the results of mammograms with CT scans of the coronary arteries. They found that there was a good correlation between the finding of calcium-laden blood vessels on mammograms and finding calcium deposits in the coronary arteries. If future research confirms this link — and, more importantly, if these mammographic findings lead to preventive measures or treatments that lower the incidence of heart attacks, strokes, and premature cardiovascular-related deaths — mammography could become a common screening test for both breast cancer and cardiovascular disease.

"Incidentalomas": More troublesome than helpful?

The finding of an "incidentaloma" — an abnormal finding that wasn't the abnormality that a test was intended to find — poses challenges to doctors and their patients. The simple truth is this: it's hard to know what to do with something you find when it wasn't what you were looking for, especially when no one is sure if what you found is useful.

This problem is not a new one. As imaging tests such as CT scans and MRIs have improved and become commonplace, more and more people are dealing with the uncertainty of the "abnormal shadow," a lump or a nodule that's of uncertain importance. A recent example is lung cancer screening by chest CT for smokers: about 25% have non-cancerous abnormalities ("false-positive" results) detected. Of course, patients and their doctors only know for sure that the abnormality is non-cancerous after a biopsy or a period of time has gone by without growth. Often these abnormalities may lead to unneeded worry, additional testing (which can be somewhat risky), and added health care costs.

The challenge — and potential — of incidental findings

Most of the time, incidental findings aren't particularly helpful. You may hear about the occasional unexpected finding that did matter — an early, curable tumor or an aneurysm ready to burst, for example. But what you don't hear as much about are the far more common "incidentalomas" that aren't helpful at all: they don't lead to any specific treatment or lead to improved health. And you also may hear little about the unneeded anxiety these findings provoke.

But, as this new study proves, incidental findings can also represent an opportunity. If mammography proves useful as a screening tool for heart disease, we'll have taken advantage of an incidental finding that, in the past, was misleading, distracting, or just plain confusing.