The Legislature and Breast Cancer: Not a Good Match
According to California law, starting on April 1, 2013 (I note that that was April Fool’s
Day), women whose mammograms revealed dense breast tissue will get the following notice:
Your mammogram shows that your breast tissue is dense. Dense breast tissue is common and is not abnormal. However, dense breast tissue can make it harder to evaluate the results of your mammogram and may also be associated with an increased risk of breast cancer.
This information about the results of your mammogram is given to you to raise your awareness and to inform your conversations with your doctor. Together, you can decide which screening options are right for you. A report of your results was sent to your physician.
I would call this silly legislation, but that is a redundant phrase for far too much that the legislature does.
What You See Is Not What You Get
Here are the problems: About 40% of women have dense breast tissue (as the notice says, it’s not abnormal). Not all dense breast tissue is associated with an increased risk of breast
cancer. And, when there is an increased risk, it’s not increased by very much. A woman who is 40 without dense breast tissue has a risk of developing breast cancer in the next 10 years of 1.47%. A 40 year old woman who has dense breast classified as grade 4, has a risk of developing breast cancer over the next 10 years of 2.38.
Dense breast tissue is categorized on a scale of 1 to 4, with 4 being the most dense. Under the current state of our knowledge about breast cancer, we “know” that 1 or 2 breast density is not associated with an increased risk of breast cancer. Women with breast density of 1 or 2 will not be notified under the law.
Women with density of 3 or 4 will be notified under the law. There’s the rub. We know that breast density of 4 is associated with a slightly increased risk of breast cancer. A woman in her 40′s with very dense breast (a grade 4) has the same risk of breast cancer as women in their 50′s. We have no evidence about whether the risk — if it is higher at all — for women with grade 3 breast density.
When Legislatures Prescribe
There are two problems with this law. One is that it requires telling women that they may be at increased risk of breast cancer when they may not be. Given that women
overestimate their risk of breast cancer to begin with, this type of notice will panic some women.
The other problem is that the law tells women to explore with their doctors which screening options are right for them to reduce the risk of a late-stage diagnosis. But the only screening option that has been shown to do this is an annual digital mammogram for women in their 40′s. Women in their 50′s with grade 4 density do not risk a late diagnosis if they have mammograms every two years. Annual mammograms for this age group which result in more false positives and unnecessary biopsies.
Medicine and Lawmakers: A Match Made Somewhere Other Than Heaven
That heading could be about abortion policy, but that is not my topic today. The legislature cannot deal with nuance. It makes broad laws that, in the best case, benefit most people on whom the law has impact. So laws that purport to mandate medical care will always miss the mark.
For a good analysis of the “dense breast” law, check the story on KQED, the San Francisco-based NPR affiliate.
Some years ago, when the first recommendations were made by scientific organizations that women in their 40′s didn’t need annual mammograms, Congressional representatives, all of were men, took it upon themselves to write laws mandating annual mammograms for women in their 40′s. They gained political points with women in their 40′s whose breast cancer had been found with mammograms. They did nothing to advance the public’s understanding of breast cancer screening issues.
The California law is no better.
© Barbara A. Brenner 2013