Breast cancer is a leading cause of death for women. Mammograms can diagnose breast cancer at an early stage and in many cases save lives. Why not just test every woman over, say 40, for breast cancer?
Well, the problem is that any mammogram will not only have false positives (diagnose a woman with breast cancer who turns out not to have the cancer) but also pick up breast cancers which are minor and won’t cause any problems.
A recent study in England revealed that for every life saved, 3 people were diagnosed with such minor cancers. In this study 1300 lives were saved but about 4,000 were over diagnosed. What, you ask, is the big deal about over diagnosis? The problem is that these poor souls are subjected to needless tests, which cost money (ok in England with socialized medicine not a lot of expenses). Furthermore, some women undergo disfiguring, unnecessary surgeries such as mastectomy; others may develop infection and are exposed to needless radiation and chemotherapy. So, in reality it is in fact important not to over diagnose.
The ideal mammogram would be able to sort out cancers, which should be investigated from those which need only watchful waiting and not diagnose cancers in patients who don’t really have cancers. Such a test, whether it is a mammogram or MRI, simply does not exist. There will always be false diagnoses and over diagnoses. The trick is to find the sweet spot: To identify that group of patients who will gain the most benefit from these tests.
Since this “sweet spot” is truly difficult to determine, it is no surprise that different groups come to different conclusions. For example, the United States Preventive Task Force recommends mammograms starting at age 50, while the American Cancer Society advises starting earlier at age 40. To make matters worse, no one wants to appear callous-that is be willing to miss some cancers to avoid false alarms and over diagnosis. And the final, perhaps most difficult obstacle is that we in America have the honor of having more lawyers than almost anywhere else on the planet. These lawyers, of course are more than willing to sue any one ( even their mother) including any doctor, who does not follow the more aggressive standard of age 40 mammograms-whether or not these standards are really the best standards.
What to do? Be aware that mammograms are not perfect. Ask a lot of questions, especially about how sure your doctor is about the diagnosis and whether you need another test to confirm this diagnosis, should repeat the mammogram or undergo further tests right away.