Study Adds Fuel to the Mammography Debate
From a Breast Cancer Symposium Sponsored by the American Society of Clinical Oncology
You might imagine that as an advocate of breast cancer screening for women ages 40–49 years, I would be dancing in the streets as a result of this report.
Sadly, I am not.
To say that this research invalidates the guidelines from the U.S. Preventive Services Task Force is a stretch.
There is nothing wrong with research itself. It's the interpretation of the research that is problematic. Headlines stating that this study validates screening mammography in women under age 50 simply are not supported by the data.
Here's what is supported by the study findings:
Focusing solely on the question of how cancers were diagnosed in women between the ages of 40 to 49, the researchers reported that 48.3% of the breast cancers were found by mammograms and 46.1% by palpation (which means someone — we don't know whether it was the woman, her physician or another health professional — felt the lump). It turns out that in press reports there were comments that in this group 90% of the lumps were felt first by the women, and 10% by their doctors).
Importantly, compared with women ages 50 and older, the younger women had a greater percentage of their cancers found by palpation.
According to the abstract, there is a slightly greater percentage of lesions found at stage 1 versus stage 2 when detection was made by mammography compared with palpation. That is an interesting and statistically significant finding, but it's not surprising and it doesn't relate specifically to women under the age of 50.
Finally, all the cancer diagnoses in the study were made prior to the 2009 USPSTF guidelines. Cancer detection rates in the study therefore reflect usual care at the time of the investigation and are not a demonstration of practice and outcomes under the guideline.
I do believe in the value of screening mammography for women ages 40 to 49 years. However, this debate about screening women in their forties that has been going for several years needs to be supported by research that is specific to the question being asked.
Let's be wary of headlines that extrapolate and draw conclusions about specific issues on which the research was not designed to address in the first place.
J. LEONARD LICHTENFELD, M.D., is deputy chief medical officer for the American Cancer Society. His remarks were summarized, with permission, from his blog,
