Viewpoint: Know the facts about dense breasts

I was disappointed to see The Tribune reprint an editorial from the Mercury News (Oct. 15) criticizing Gov. Jerry Brown’s veto on the mandatory disclosure of the presence of “dense breasts” on a mammogram. I believe that editorial was written without knowing the facts about dense breasts:

1. Radiologists use the term “dense” when the percentage of breast tissue outweighs the percentage of fat in a woman’s breast. It is a subjective term.

Radiologists classify a woman’s breast as “fatty,” “moderately dense” or “extremely dense” based on what they see on the mammogram, but there is no calculation or guidelines on the use of these terms. Furthermore, studies by the American College of Radiology show that there is little consistency among radiologists and even with the same radiologist when characterizing a breast as “extremely dense.”

Given the same mammogram, one radiologist might categorize a breast as “extremely dense” while another would categorize it as “moderately dense.”

2. There is no scientific evidence that having even “extremely dense” breasts places a woman in the “high-risk” category for developing breast cancer. (“High-risk” means having a greater than 20 percent lifetime risk of developing breast cancer.)

3. Screening beyond a mammogram has been shown to be medically justifiable and cost-effective only if a woman is “high-risk.” Currently, the only proven method to screen high-risk women is breast MRI, a costly test that should be used selectively only in this population.

4. With the advent of digital mammography, the ability to diagnose cancer, even in women with extremely dense breasts, has improved markedly.

5. Breasts become less dense as a woman ages. Beyond menopause, when breast cancer risks increase, most women do not have dense breasts.

Obviously, every woman wants to be as informed as possible about her health, but I don’t believe SB 791 would have provided beneficial information. SB 791 would have required that all women with dense breasts receive mammogram result letters stating: “You might benefit from supplementary screening tests, depending on your individual risk factors.”

Receiving such a letter may have increased patient anxiety and imply that the woman’s mammogram was ineffective, which is simply not true. Furthermore, if a woman is informed that she has dense breasts, she may not be able to do anything with that knowledge. SB 791 did not require insurance companies to pay for any additional screening tests. Currently most insurance companies will NOT authorize an MRI for screening unless a woman is “high-risk.”

Women who want to know if they are high-risk can find a Breast Cancer Risk Calculator online. A number of programs are available to calculate their lifetime risk. Knowing if a woman is high-risk is definitely a better indicator of her chance of developing breast cancer than knowing if she has dense breasts. For those women who want to know if they have dense breasts, this information, as subjective as it is, is provided in the mammography report that is sent to their referring physicians.

Fred S. Vernacchia is a radiologist and medical director at San Luis Diagnostic Center.