Changing the Screening Paradigm: Follow-Up Ultrasounds for Women With Dense Breasts

Photo Courtesy © SABCS/Todd Buchanan 2014

Jean M. Weigert, MD, FACR

In 2009, Connecticut became the first state to enact legislation mandating that patients undergoing mammography be informed of their breast density and the option to have a follow-up ultrasound. To assess the impact of the new program, Jean M. Weigert, MD, FACR, head of breast imaging for the Hospital of Central Connecticut, conducted a retrospective chart review to see how well it worked in detecting cancers in women with dense breasts during the first 4 years of implementation.

Her study, reported at the 2014 San Antonio Breast Cancer Symposium, found that this supplemental ultrasound screening of dense breasts did detect a significant number of breast cancers not discovered by a mammogram.¹

Breast density reporting laws are now in effect in 21 states, and bills were introduced in several others this year. At the federal level, the “Breast Density and Mammography Reporting Act of 2015” is pending in the House of Representatives and the Senate (HR 716/S 370). Oncology Nursing News sat down with Weigert to discuss her research and learn more about how breast density reporting is working in practice.

What was the impetus for your study?

Back in 2009, then Connecticut Governor Jodi Rell, a breast cancer survivor herself, signed a law mandating that patients be informed of their breast density—whether it was less than or greater than 50%. As part of that mandate, clinicians were to explain that if women had breast tissue density greater than 50%, they might want to talk to their doctors about supplemental imaging with breast ultrasound; 2 years later, breast MRI was included as an adjunct as well.

This legislation was the first in the nation, and it was groundbreaking because AreYouDense.org, a grassroots group of breast cancer survivors, really pushed to have this done. In 2007, I testified before the state legislature as a delegate from our state radiology society against this legislation because we didn't feel that there were enough data to support it. But when the ACRIN [American College of Radiology Imaging Network] 6666 study documented that they could find an additional 4.2 per thousand cancers ² in women who had high risk, it certainly became untenable for us to not go ahead and say okay, now there are data, and I thought this presented a great opportunity for a small state to gather more. Working with a medical student from the University of Connecticut, in the first year we collected data from 12 sites around the state, and the data were published in Breast Journal in 2012.³

We then gathered the data for the second year and observed similar findings—approximately over 3 additional breast cancers per thousand, which basically doubles the number of breast cancers that we find on just screening mammogram alone. I also was still collecting this data in my practices and decided to continue to do this for a few more years because 1 or 2 years really doesn't provide enough information. We didn’t know whether the numbers would fall off, whether people would even come, and what kind of cancers we would find. There was still a great deal of skepticism around the country, but at the same time, more of these breast density reporting bills were being signed; this was a unique opportunity.

I pulled out the data from my five offices for the years 1 through 4. I tallied it all up, compared it, and found—much to my surprise—we continued to find 3.2 additional cancers per thousand cancers in this cohort of patients with breast tissue density greater than 50%.

What did your study find with respect to women with dense breasts actually getting the follow-up ultrasound screening?

Over the 4 years, we were still only getting about 30% of women coming in who were eligible because of their breast density, despite the fact that Connecticut is one of just a few states where insurance covers this with just a code of "dense breast tissue." Still, there are certainly a lot of high-deductible plans, so women are being cautious. They may not come back for this if they have a high deductible and do not want to pay for the ultrasound (average cost about $100). As we get more education out, and now with 4 years of data, I think that is enough to show that this is a worthwhile study.

Is there an issue with false positives?

Many lesions that we find on ultrasound may not be cancer, and certainly in years 1, 2, and 3, a significant number of biopsies did not need to be done; they were false-positives. But between years 3 and 4, we jumped from about an 8% positive predictive value to 17.2%, and I think that that will only get better. That's a huge improvement, and something that the naysayers will have to look at and say “oh, yes, there was a learning curve.” It takes a few years when we have new technology. When we started to do screening mammography, we certainly were conducting biopsies that we didn't need to. But our positive predictive value for regular screening mammography overall—any density—is about 20 to 30%, so we're clearly getting into that range, and I see no reason why it isn't going to improve.

Are women aware of the importance of knowing their breast density and the need for follow-up screening?

There's clearly an awareness issue. Referring doctors, at least now in my community, they order it immediately. And what we've done to make that easier for them is give them a “reflex to ultrasound if dense” order sheet so that when they order their patient's yearly screening mammogram, they just check that off; we don't need to call them for another order, and the patient doesn't need to call their doctor for an order. When they get their letter that says, “You do have dense breast tissue,” patients can just call any one of our offices around the state. Many facilities around the state have developed these reflex-to-ultrasound requisitions that have made it simpler for everybody to get their studies done.

And, ultrasound is readily available, there's no radiation. Automated breast ultrasound tools are now emerging that speed up our ability to perform this test on patients.

That being said, there are a lot of women who do not want to have it done, and that's certainly up to them. You can't make someone have a screening mammogram either, obviously. But once women are told their breasts are dense, and they see it, they are very comfortable in coming in. And now we're having patients coming back every year, and we're finding that in some women who had previous ultrasounds, we're finding cancers under a centimeter in size.

We don't know when we would find these cancers, had they just waited with their mammogram—when would they become palpable, when would they be visible within the dense breast tissue on the mammogram alone, what the size differential would be, and, therefore, the difficulty in treatment. We know with breast cancer, there are so many different kinds. You have women who come in for a mammogram, have a small high-grade cancer, and we still don't have the positive outcome that we'd like. By identifying a lesion when it is smaller, it will be less costly to treat and certainly less stressful for everybody.

Do you see, based on your findings or other studies as well, this becoming part of standard practice?

National legislation has been proposed, but of course in this political climate, whether something like this will ever go through is hard to tell. The FDA’s Mammography Quality Standards Act and Program (MQSA), the governing body that actually comes in and inspects all of our sites and mandates that we give patients plain language reports, is looking into adding a breast density notification as well. If that happens, then we don't really need any other legislation; it will be just come down to awareness.

I don't think this should be anything that anyone should be fearful about. I think all patients have a right to know the most about their bodies. You don't want to hide the fact that your cholesterol is high; you want to know about that. We want to look at this as a risk assessment tool that changes the paradigm perhaps of how we screen women for breast cancer: Low risk: just a mammogram every year; High risk (eg, BRCA patients, strong, strong family history): mammogram plus probably an MRI; and then, in the middle, is a group of women who have no significant other history, maybe some low-grade family history but do have higher breast tissue density: add the screening ultrasound as part of their routine imaging.

We have to think outside of the box; it's a new paradigm, something that even I, only recently with this data, had an epiphany about myself. So I think it's quite exciting.

References

• Weigert JM. The Connecticut experiment: 4 years of screening women with dense breasts with bilateral ultrasound. Presented at: San Antonio Breast Cancer Symposium; December 9-13, 2014; San Antonio, TX. Abstract S5-01.
• Berg WA, Blume JD, Cormack JB, et al. Combined screening with ultrasound and mammography vs mammography alone in women at elevated risk of breast cancer. JAMA. 2008;299(18):2151-2163.
• Weigert J, Steenbergen S. The Connecticut experiment: the role of ultrasound screening of women with dense breasts. Breast J. 2012;18(6):517-522.