Mammograms are often thought of as the first line of defense in the war on breast cancer. Many breast cancer organizations, such as Komen, pay for mammograms for women who can't afford them. On its face, this seems like a good thing. Why not screen women for breast cancer? It couldn't hurt, and it could only help, right? In fact, one of Komen Massachusetts’ goals is “committed to 100% screening. “
There are several reasons why mammography isn’t always a good idea. Whenever you start screening a population as opposed to individuals with a particular risk factor, you find a lot of things that aren't really problems, but once you find them, you have to do something about them. This is called over-diagnosis and over-treatment. Over-diagnosis and over-treatment is something that drives me absolutely crazy. Thousands upon thousands of women are diagnosed with DCIS (ductal carcinoma in situ, or stage zero breast cancer) and treated with surgery, radiation, and hormones for cancers that, in some cases, could just be left well enough alone. The big problem right now is that we have no way of predicting which cancers will go on to cause harm, and which ones are slow growing and will probably not cause harm. So we have to treat everything as if it's harmful. That's over-treatment.
On the other side of the spectrum are women with dense breasts for whom mammography isn't that useful. The density makes it hard for the radiologists to see the abnormalities. This creates a false sense of reassurance when in actuality, a tumor is growing.
Mammograms are not the be-all, end-all that we've been led to believe. They are a tool, and for some women, especially those whose breasts aren't dense, they can be a good tool to detect tumors that are too small to feel.
For younger women, however, whose breasts tend to be dense, mammograms aren't so great. About 40% of women have dense breasts. For these women, breast MRI and/or ultrasound may be a better choice. (Here is a great article on breast density.)
I am one of those "dense-breasted" women. Because my mother had breast cancer at 47, I was considered at high risk, so I had yearly mammograms from my mid-30s through my 40s. Some years providers would find a lump, and do some additional testing, and then send me on my way. "Everything is fine," they'd say. Until it wasn't.
My breast cancer was discovered by my primary care doc who was doing a physical exam of my breasts. There was a firm lump in my right breast that she hadn't felt 6 months before, and which hadn't been there when I had my last mammogram. The thing is, breast cancers take 8 or 10 years to grow in a breast, so my cancer had been there for a quite a while, undetected by mammography.
According to Archie Bleyer and H. Gilbert Welch, two physicians who wrote a recent article in the New England Journal of Medicine, increased screening over the past 30 years in the U.S. has led not to decreased mortality (breast cancer deaths) but to increased over-diagnosis, which is to say, many women (about 30 percent) whose cancers would never have caused harm have been treated for those cancers with guns blazing (over-treatment).
I worry that I was one of those over-treated women. If my cancer was really there for 8 or 10 years and not causing any problem, and not spreading, did I really need 2 surgeries, radiation, hormonal therapy and all the rest? It's not that I'm not grateful for the care I received. It's that I wonder whether it was all necessary. Right now, there is no way of knowing. Hopefully some day we will know, and can avoid over-treating women. Women -- like me.