New York’s Breast Density Law – TMI with TLI for Too Many Women

MOST RECENT POST ON THIS ISSUE  Dense Breasts on Mammogram. No need to be Afraid.

Once again, legislators are meddling into healthcare. This time, it’s in my own home state, where Governor Cuomo has just signed a bill requiring radiologists to notify women when their normal mammogram also shows that they have dense breasts. In such cases, the following text must be included in the lay summary mammogram report given to the patient –

“Your mammogram shows that your breast tissue is dense. Dense breast tissue is very common and is not abnormal. However, dense breast tissue can make it harder to find cancer on a mammogram and may also be associated with an increased risk of breast cancer.

This information about the result of your mammogram is given to you to raise your awareness. Use this information to talk to your doctor about your own risks for breast cancer. At that time, ask your doctor if more screening tests might be useful, based on your risk. A report of your results was sent to your physician.”

New York is the fifth state to pass a mandatory breast density notification law. As of this writing, Connecticut, Virginia, California and Texas have similar laws.

What is Breast Density ? 

Breast density is a subjective radiologic assessment of how well x-rays pass through the breast tissue. It is a surrogate for how much of the breast is composed of glandular tissue and how much is fat. The radiologist reading the mammogram classifies the breast composition as one of the following  –

  1. Almost entirely fat (<25% glandular)
  2. Scattered fibroglandular densities (25-50%)
  3. Heterogeneously dense breast tissue (51-75% glandular)
  4. Extremely dense (> 75% glandular)

For the purposes of the law, dense breasts are defined as those that are heterogeneously dense or extremely dense.

Mammographically dense breasts are extremely common, especially in younger women. According to a recent report of mammograms here in New York City, 74% of women in their 40s, 57% of women in their 50’s, 44% of women in their 60’s and 36% of women in their 70’s had dense breasts.

What We Know (and Don’t Know) About Breast Density

Increased breast density can be a risk factor for breast cancer . 

The mechanism is unknown, but it may be that breast density is just the end result of other factors that increase breast cell proliferation and activity – factors like genetics and postmenopausal hormone use.

How much of a risk? Well, it depends on what study you read and who you compare to whom. If you compare the two extremes of breast density in older women, those with extremely dense breasts have a three to five-fold higher cancer risk than those with mostly fatty breast. The risk is lower than that in those in the middle category of breast density and in younger women, though not well-defined.

The truth is, we really have no way to translate individual breast density into individual risk. Researchers are trying to see if breast density can be incorporated into current risks assessments such as the Gail Model, but at this point, breast density has not been shown to add much more than we already know about a woman’s risk from using these models.

Dense breasts can obscure a cancer on mammogram.  

This makes mammogram less reliable in women with dense breasts. Digital mammograms may be better at finding breast cancers in women with dense breasts who are also peri-menopausal or < age 50, but it is not known if this translates into better outcomes.

Additional testing with ultrasound and MRI can find cancers that mammograms miss in women with dense breasts. Unfortunately, breast ultrasound and MRI screening tests are less specific than mammograms – three times as many biopsies will be done, most of which will not be cancer.

We do not know if additional screening beyond mammograms saves lives.

It might seem to makes sense that it would, but there are no randomized trials to show this. For now, this additional screening is only recommended in women at highest risk for breast cancer based on other factors such as genetic, family and personal health history.

Why the Breast Density Law is Misguided

Our legislators have women’s best interests at heart, but unfortunately, when it comes to the practice of medicine, they really don’t know what they are doing. Allow me to explain…

1.Most women under age 60 have dense breasts.  

Three quarters of New York women in their 40’s, all of whom have just had a normal mammogram, will now be told that they may be at increased risk for breast cancer.

2. Breast density measurement is subjectiveDifferent radiologists may give the same mammogram different ratings. Use of computerized density measurement could alleviate inter-observer variability, but there is not yet a standardized computer rating system.

3. Breast density can vary across a woman’s menstrual cycle and over her own lifetime. The same women being scanned at a different time of month or at a later year can land into a higher or lower breast density category, and may or may not get that letter above. Recent research suggests that a single breast density reading may not be the best way to predict breast cancer risk, and that the risk may be confined to those women whose breast density does not decrease with age.

4. Sonogram and/or MRI for breast cancer screening is currently not recommended based on breast density alone. Additional screening beyond mammography is only used in women at highest risk for breast cancer  – those with cancer in a first degree relative with a high risk gene mutation, a family history suggesting one of these mutations, a Gail model or other combined lifetime breast cancer risk assessment >25% or a history of chest irradiation. Even in this group, declines in morality with the additional screening have not yet been shown, and the false positive rate of this additional testing is extremely high – only 20% of abnormals are cancer  when biopsied.

There are no recommendations to use sonogram and MRI in otherwise low risk women, and none that have shown that using it based on breast density alone saves lives.

5. Additional screening adds significant costs to breast cancer screening.  For some women, this additional cost may not be covered by insurance. While Connecticut has passed a law mandating that insurers cover additional sonograms, New York State has not.

6. The law is a medico-legal nightmare.  The legislators are creating a medical standard where there is none. That however, has never stopped the lawyers.

I would expect a lot more business for radiologists doing defensive breast ultrasounds ordered by referring docs who don’t want to get sued for a missed diagnosis by a woman with dense breasts. After the first breast density law passed in Connecticut, the use of ultrasound in that state skyrocketed.  (The American College of Radiology, by the way, urges caution on breast density legislation.)

I would also expect a lot more lawsuits for missed diagnosis aimed at the referring physicians whenever dense breasts are noted on a mammogram, even if that woman had no other risks factors for breast cancer.

7. The EMR Makes This Law Unnecessary. As EMR use expands, women will be able to read their actual radiology report online. Those who want to know their density will, and the rest will not be unnecessarily alarmed.

8. The law violates the free speech of physicians. This regulation did not originate from within the medical community or the department of health. It is a lay attempt to push screening beyond what the evidence supports at this point in time, and to set a medical standard (ultrasound for every woman with dense breasts) that does not exist.

At This Point, What Can be Done?  

Short of radiologists filing a lawsuit claiming free speech violation ? (Not a bad idea I think…)

We have 180 days before the law takes effect. In that interval, I would recommend that the New York State Health department come up with some educational materials on breast density that informs rather than frightens women. They could include information about breast cancer, mammograms in general, their limitations, benefits and harms. And tell women what to do and where to go if they feel a lump or have a breast symptom.  This additional material can be included with the report so that women actually get the information they need about breast cancer screening, rather than an unexpected scare when what they thought they had just gotten was a normal mammogram.

Hmmm, that’s actually not a bad idea…If someone wants to pass a law that Department of Health written breast cancer screening info be given out at the time of Mammography, I’d get behind it in a second.

But telling the majority of women in their 40’s who have just had a normal mammogram that they may be at increased risk for breast cancer? That’s just wrong.

9 Responses to New York’s Breast Density Law – TMI with TLI for Too Many Women

  1. Thank you – this is fascinating. I’ve always been told that I have dense breasts, and sometimes they make me get a sonogram. Your arguments as to why this a bad law are terrific.

  2. Hi Peggy,
    I think the law is, on balance, helpful to women. The language is imperfect; I’m not convinced that women with dense breasts are at increased cancer risk. And, as you point out, breast density changes during the menstrual cycle. But if a woman has dense breast tissue that renders a mammogram uninterpretable, she should know that, and she should be offered a sonogram to clarify the picture.

    • Elaine –

      It appears that in many ways we agree – the language of the law is not good and there is not yet convincing data that breast density as an individual risk factor is relevant, especially in younger woman. That was the entire point of this post.

      Where we disagree is whether the law is helpful – I think on balance it is not.

      The goal to inform women about breast cancer screening is laudable – but pulling density out of the entire picture for special attention and then couching that attention in fear-mongering (really? 75% of women under age 50 may be at increased risk of breast cancer? – I guess putting in “May be” makes it technically correct, but that doesn’t change how it feels to a woman to read that she may be at increased risk for cancer.) and then suggesting additional screening to the majority of women under age 60 without data to support it is not the way to go.

      Every woman is an individual and as physicians, we do our best to balance the risks and benefits of screening based on a host of factors – family history personal history are important, as is breast density and physical exam and our patient’s concerns.

      We’ll see how things go as the year progresses with this new law in place. I may change my tune, but at this point I see huge problems with this as a practicing physician who orders mammograms for many women in their 40’s and 50’s.

      All the best,


  3. What it will mostly do, besides feed lawyers, is scare the bejabers out of people. But why a law at all? Remember when medical care was the province of doctors and not legislators?

  4. All good points (except maybe for the free speech argument which I dont think holds much water)….I really think that these laws are being pushed by (and the fear generated by) manufacturers of US equipment (particularly the whole breast automated scanners that are being promoted for screening US). The ironic thing is that our federal govt. is telling us maybe we should be doing less mammography for women in their 40’s – not because it doesnt find cancers, but because of the “harm” from false positives, the fact that you have to screen more young women to find the cancers, and you find some cancers that may not have killed the patient (I wish the cancers would tell us which ones). Yet our state is telling us to do more screening US, which has MORE false positives, requires screening MORE patients to find the same number of cancers, and there is not a single study showing that finding these “extra” cancers affects the patient survival.

  5. I agree with Elaine. Informed consent is the cornerstone of modern medical practice. It wasn’t that long ago that physicians withheld information from patients (especially women) “for their own good.” Too much information is better tha none at all.

  6. If the goal of the law was to scare the bejeepers out of me when I opened my mail and received results saying additional mammograms recommended due to scattered fibroglandular densities, mission accomplished.

  7. It was never standard practice for doctors to inform patients they had dense breasts. subsequently, she could have been at risk for many years unknowing she was at risk for breast cancer. So for many patients this state mandated law is useless.

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