Lisa Stempel, MD, is chief of the Division of Breast Imaging at RUSH. Here she answers key questions about breast cancer screening, including who should be screened and how often.
Why are breast cancer screenings so important?
Mammography is probably the most vigorously studied test in all of medicine and it is undisputed that screening mammography saves lives from breast cancer. So for women who are actually screened, there's about a 40% decrease in mortality from breast cancer. Breast cancer that we can detect on a screening mammogram has a much better prognosis than breast cancer that has been detected because a patient will feel a palpable lump. A breast cancer that we find that's still confined to the breast can have up to a 99% five-year survival rate, whereas a breast cancer that's been allowed to spread outside the breast and to metastasize to other places has about a 29% five-year survival. So it's extremely important to catch breast cancer early when we can treat it
There are certainly other benefits to finding breast cancer early, in addition to the very important benefit of decreasing mortality. These benefits include being able to avoid chemotherapy or at least having less frequent or toxic chemotherapy, being able to have a lumpectomy, which is a much smaller surgery instead of removal of the breast with a mastectomy, and being able to have a smaller surgery in the underarm to sample lymph nodes with a sentinel lymph node biopsy instead of the full axillary dissection biopsy, with a much lower resulting complication of lymphedema in the arm. So there are a lot of benefits to catching breast cancer early, and mammography is the only test proven to decrease mortality.
Are there other screening methods available now at RUSH?
At RUSH, we do a personalized screening for breast cancer. All women 40 and up are recommended for yearly screening with tomosynthesis — that's 3D mammography. But we also offer all women the opportunity to participate in a cancer risk assessment program, and we use validated risk models to determine a patient's lifetime risk of breast cancer, to determine if they qualify for risk reducing medication, and to determine if they qualify for genetic testing to see if they have a genetic mutation. And we use the results of this cancer risk assessment and the density on their mammogram to determine the best screening for each woman based on her unique characteristics.
So for example, if a patient is high risk, we will offer them MRI or possibly contrast mammography. If a patient is at average risk but they have dense breasts, we offer them ABUS, which is an automated breast ultrasound.
What does it mean to have dense breast tissue, and how common is it?
Dense breast tissue is very common. Forty percent to 50% of the population has dense tissue, and the only way to determine who has dense breast tissue is by looking at a mammogram. It doesn't matter what a physical exam shows when you do a physical exam of the breast. It has to be determined by a mammogram. And basically, it's determined by the ratio of fat in the breast, which looks black on a mammogram, versus glandular tissue, such as lobules that make milk, ducts that deliver milk and the supporting structures, and they look white on the mammogram. So the more glandular tissue you have versus fat, the whiter the mammogram looks.
This matters because we're looking for small white cancers, and the white tissue can mask those cancers. Density itself is also an independent risk factor for breast cancer. It does make you higher risk for getting breast cancer. Because of this, 38 states have actually enacted laws called breast density notification laws, and Illinois has one of these laws, and there's a national law pending right now. And this is so that women who have dense breasts are notified that they have dense breasts so that they can pursue supplemental screening, additional screening with things like ultrasound so breast cancer can be seen and not masked by the breast density. This will allow women who have dense breast tissue the benefits of early detection, just like women who have non-dense breast tissue.
At what age should women get screened, and how often?
We at RUSH believe, and so many other societies like the American College of Radiology and Society of Breast Imaging, that all women should start screening at age 40, and they should screen every year. They can continue screening until they have about five years of life expectancy left. In fact, women who are — like 75 to 85 — if they continue screening during those years, they have a 50% decreased chance of mortality from breast cancer versus women who stop screening at 75.
Unfortunately, there's a lot of extremely confusing recommendations out there, with certain societies giving different recommendations, like the U.S. Preventive Services Task Force and the American Cancer Society, where they recommend screening at 45 or at 50 and then screening every other year for certain decades and every year for certain decades. Though everyone does acknowledge if we want to save the most lives, we will start screening yearly at age 40, there's still a lot of confusing recommendations out there, and it's really important that women know that breast cancer is quite common between the ages of 40 and 50.
One out of every six breast cancers are diagnosed during this decade. That's about 10,000 people a year in this country. And it's extremely important that younger women get screened because it's so common, but it's also important that they screen every year, because the breast cancer that younger women get is often more aggressive, metastasizes more quickly, so we have a much shorter window to catch that breast cancer, and we don't want them going two years without a mammogram.
Does that age or cadence of screening change for women with a family history of breast cancer?
We do recommend that anyone with a family history of breast cancer in a first-degree relative, which is a sister or mother, start their screening 10 years before their relative was diagnosed. But we do recommend also that anyone with a greater than or equal to 20% lifetime risk of getting breast cancer, which family history does contribute to, has a breast MRI in addition to mammography. And we like to do yearly MRI and yearly mammography offset by six months. MRI is the most sensitive way we have to screen for breast cancer, and mammography is less sensitive in high-risk women, which is why we really like to add MRI in for these women.
Some people believe that the risk of developing breast cancer is much, much smaller for those without a family history. What are the facts?
Unfortunately, that is not true, and women cannot feel safe by not having a family history because only 15% to 20% of women who are diagnosed with breast cancer have any known family history of breast cancer. So it's extremely common to get breast cancer with no family history. In fact, 75% of women who get breast cancer are considered average risk and have no family history. So we really need to screen all women, not based on their family history and not based on their risk level.
What are some of the common myths that you've heard from patients about the experience or risks associated with mammograms?
The harms or risks that are most discussed when speaking of mammograms include pain, that the mammogram is painful. But I will tell you, I have never met a woman who cannot withstand the momentary pain of the compression of the breast.
Another thing some people get concerned about is radiation exposure. And it's really important to know that the radiation from a mammogram is extremely low. It's similar to being in an airplane for two hours, to being on Earth for two months. It's just an extremely low dose of radiation.
Another harm people talk about is the anxiety from being called back from a screening mammogram that's incomplete or from the rare needle biopsy. But this anxiety, though it is stressful to be called back or to have to undergo a biopsy, this anxiety has actually been studied and it's been shown to have no long-term effects. And in the studies, they found that most women would not forgo the benefits of early detection because of that short-term anxiety.
The final risk or harm that people talk about when they talk about mammography is something called over-diagnosis. And that means that we find a cancer on screening that would not become apparent during that patient's lifetime. This is really not an issue for young women. Over-diagnosis accounts are far under, far less than 1%. Older women who may die from another cause, it can sometimes become an issue, but it's extremely rare, and the benefits of early detection certainly outweigh that risk.
Are there certain populations with higher incidence of breast cancer or more aggressive forms of it?
Yes, actually, very much so. Black women are truly disproportionately hurt by any recommendations that do not recommend screening beginning at age 40. Black women are diagnosed at younger ages than white women. In fact, 23% of breast cancer in Black women is diagnosed in the decade of 40 to 50, whereas only 16%, which is still a large number, but not at not as large as for Black women, get breast cancer diagnosed between 40 to 50. So if Black women are not offered screening mammography at the age of 40, we will miss the chance for an early detection in many of these women.
It's also very important to offer Black women yearly mammography and not mammography every other year because they have a propensity to get a more aggressive breast cancer called a triple-negative breast cancer. And that breast cancer can metastasize more quickly, it's more aggressive. Just like with younger women, we have that shorter window where we want to catch that breast cancer in order to offer the benefits of early detection
Are there circumstances besides dense breast tissue that can make screening for cancer more difficult?
Breast implants can cause some difficulty in visualizing the entire breast, but we do have ways of pushing the implant aside and compressing the breast tissue. It's unlikely we can see as much breast tissue when there's an implant in place as when there's not. And sometimes we do need to go to supplemental screening to see more breast tissue because the implant can block our view.
But other things that cause problems with screening, sometimes certain surgeries can make it, like a reduction surgery sometimes can cause some issues right when it happens because it's hard to tell if the scarring is a new worrisome type of distortion or just scarring distortion. But we can usually figure those things out.
We also know that some men can get breast cancer, but it is quite rare. Should some men also get screenings, especially if there's a family history?
Breast cancer is extremely rare in men. Less than 1% of all breast cancer diagnosed occurs in men. But there's certain men who are at higher risk for breast cancer. Certainly men who have tested positive for the deleterious mutation of the BRCA gene, the BRCA1 and BRCA2 genes, have a higher risk of breast cancer. Right now, the only men who are recommended for screening mammography are men who have the deleterious mutation of the two BRCA genes and gynecomastia, not just the mutation. That's the recommendation right now. Gynecomastia is a benign enlargement of the breasts in men due to an increase in fibroglandular tissue. The combination is said to make men high enough risk that they're recommended for screening. And right now, the recommendations are starting at age 50 or 10 years earlier than their earliest relative was diagnosed.
Science has done very little study in how certain conditions affect transgender individuals. And I was thinking, do we know anything about whether transgender women or men have sometimes unknown risks of breast cancer?
There's not a lot published about that. Certainly, we know that hormones can increase the risk of breast cancer. That has been shown. There are recommendations. The American College of Radiology does have recommendations for screening for patients who are transgender. And it takes into account the sex they're assigned at birth, the use and the duration of the hormone therapy exposure, and any surgeries they've had. But the recommendations are really based mostly on expert opinion and very limited data at this point.
How does genetic testing fit into the picture?
Genetic testing is becoming more and more common. Thankfully, it has become less expensive and easier to pursue. And there are laws that protect people now from insurance companies discriminating against them because of genetic mutations. Because of that, there's a lot more genetic testing out there and there are a lot of breast cancer genes, and genes for other diseases as well, that we can test for. And certainly, many people have heard of the BRCA genes, BRCA1 and 2, which causes a significantly increased risk of breast cancer and ovarian cancer. But there are other genes as well.
Here at RUSH, we actually run patients' history through the NCCN data requirements. NCCN is the National Comprehensive Cancer Network, and they have a list of multiple different possible family histories that qualify people for genetic testing. And so we have found that there are a significant number of our patients who qualify for genetic testing.
The reason why it's a good idea to think about getting genetic testing if you qualify is that we will screen you differently if you have one of the genes that significantly increase your risk of breast cancer. Certainly, if it increases it to over 20, greater than or equal to 20% lifetime risk, then we are going to offer MRI because it's such a sensitive way to screen for early breast cancer. And then we also offer contrast mammography for patients who don't or can't pursue MRI.