Science Friday - New Guidelines Recommend Earlier Breast Cancer Screening

Episode Date: May 20, 2024

The U.S. Preventive Services Task Force has updated its recommendations for breast cancer screening once again. The recommendations now stipulate that women and people assigned female at birth should begin getting mammograms at age 40, and continue every other year until age 74. The previous guidelines recommended beginning screening at age 50. These guidelines carry a lot of weight because they determine if mammography will be considered preventive care by health insurance and therefore covered at no cost to the patient.Why have the guidelines changed? And how are these decisions made in the first place? To answer those questions and more Ira Flatow talks with Dr. Janie Lee, director of breast imaging at the Fred Hutchinson Cancer Center and professor of radiology at the University of Washington School of Medicine.Transcript for this segment will be available the week after the show airs on sciencefriday.com. Subscribe to this podcast. Plus, to stay updated on all things science, sign up for Science Friday's newsletters.

A National Task Force recently updated breast cancer screening guidelines. Supporting screening earlier will enable more women to be diagnosed earlier before their cancers can present with symptoms and help us prevent deaths for breast cancer. It's Monday, May 20th, and you're listening to Science Friday. I'm SciFri producer Shoshana Bucksbaum. The U.S. Preventive Services Task Force recently updated its guidelines once again for breast cancer screening. Women and people assigned female at birth should be given. getting mammograms at age 40 and continue every other year until age 74. Now, the previous guidelines recommended beginning screening at age 50.

But why have the guidelines changed and how are these decisions being made in the first place? Here's Irafledo with more. Joining me now to answer these questions is my guest, Dr. Janie Lee, director of breast imaging at the Fred Hutchinson Cancer Center and at the University of Washington School of Medicine in Seattle. Dr. Lee, welcome to Science Friday. Hi, thanks for having me. Nice to have you. Let's start with an overview of the changes to the breast cancer screening guidelines, please. Why did the task force come to the decision to lower the screening age? The United States Preventive Services Task Force,

also known as the USPSTF, has a pretty rigorous process for evaluating evidence to help them update their guidelines. And they do this periodically. As you know, the last guidelines were issued in 2016. And so in preparation for these new guidelines, they did what they call a systematic review of the literature that has been published. And they also commissioned a decision analysis to help them better understand how to use the evidence that has been published to improve the guidelines. And so they specifically looked at studies have been published in the last decade.

And those reports indicate two important things. One is that breast cancer diagnoses in women in their 40s have increased substantially in the past decades since the last recommendations were issued. And in addition, there's note that black women are increasingly more likely to develop biologically aggressive cancers, which grow faster and spread faster and tend to be diagnosed in more advanced stages compared to women of other race and ethnicity groups unless they have a higher rate of breast cancer deaths. And so the guidelines were revised to begin starting at age 40 instead of age 50.

And hopefully supporting screening earlier will enable more women to be diagnosed earlier before their cancers can present with symptoms and help us prevent deaths for breast cancer. Interesting. I want to get into those individual facts a little bit later, but I want to know first, what do you make of these guidelines? Is this in line with what you think should be happening? These new guidelines are definitely good news. As you know, there are multiple organizations that issue screening guidelines, and they vary. And particularly starting age has been variable across the organizations that issue guidelines. And so updating the USPSTF guidelines to start at age 40, better aligns with other guidelines

that have recommended starting at age 40, including the American College of Radiology and the National Conference of Cancer Network. people might be thinking, well, then why did they move the screening age back to 50 in 2009? I mean, the 2002 version began screening at 40, right? Well, first of all, if we can back up a little bit, I do want to be very clear that the evidence is strong and clear that nomography saves lives. There are clinical trials called randomized clinical trials that are considered of the highest quality that have established that screening mammography saves lives. Everybody is in agreement about that. The devil, as you say, is on the details.

When do you start? How frequently do you screen? And so the starting age has been a little controversial because different organizations have different perspectives on how to balance the benefits and the harms of screening. And so what we know is the age-specific incidence of breast cancer, which is how many cases of breast cancer are diagnosed each year among women in different age groups. increases between the 40s and the 50s and the 60s. And so there's just more cancer to find in women in their 50s and 60s versus women in their 40s.

You want to balance that with the potential harms of screening. The false alarms associated with having a positive screening test being asked to come back for additional imaging, maybe having a biopsy that turns out not to have cancer. If there's less cancer to find, there tend to be more false alarms. And so what is the right age to start screening and to balance those benefits when harms is, is determined by each organization when they have those discussions. That is why that new information that breast cancer diagnoses are increasing substantially in women in their 40s has shifted their perspective of the USPST.

Do we have any idea why this is happening? Why are women getting cancers earlier? Oh, boy, that is a really complicated question. It has to do with a lot of factors. There's sort of underlying biology. There's exposures. You know, it's not just breast cancer. People are being diagnosed with colon cancer earlier, too.

So is there something about our diet? Is there something about our habits? Are we exercising more? Are we exercising less BMI, which is body meth index, is also increasing. Is that a contributor? You know, there are a lot of really interesting questions and lots of people studying this. So, you know, I think the answer is not entirely clear, but it is being studied. Right, right. And speaking of that, you mentioned this earlier, and I want to dig into this a bit more.

What are the benefits of earlier screening for black women specifically? Well, it's because there are cancers more likely to be biologically aggressive than we want to be screening earlier and potentially more frequently, right? Like if you have a slower growing cancer, if you screen every other year, you might have a good chance of catching it. But if you have a faster-growing cancer, you want to be screening more frequently, say, every year, to have a good chance of catching it before it presents with a lump or other symptoms. You can catch it earlier before it has spread, say, to the lymph nodes, you have a better chance of curing the cancer and curing the cancer with less aggressive treatments that are more focused. Now, I know the task force

did not make a screening recommendation in this report based on breast density, but this is an important factor that scientists are looking at. And can you tell me about what we know about breast density and the risk of developing breast cancer? Breast density is one of several important risk factors for developing breast cancer. It's an interesting one because not only is it a risk factor, it is a factor that influences our ability to use mammography to detect breast cancers. And that is because breast density, which reflects the amount of glandular tissue, which is where your ducts run and fibrous tissue, which holds everything together in your breast,

relative to the fatty tissue in your breast, is white on a mammogram, whereas fatty tissue looks gray. And cancers also tend to look white on a mammogram as well, so it can make it a little bit harder to detect. Now, that being said, having breast density doesn't automatically mean that a woman is at high risk for breast cancer. I think there's a little bit of confusion there. It's certainly an important risk factor of consider,

But when you think about your individual risk, you want to consider additional factors like family history. And not only just family history, yes, we're all, but family history in terms of first degree relatives, number of first degree relatives, age, which they are diagnosed. So if you have a family history of breast cancer, the guidelines may be a little bit different for you then. Well, you know, the guidelines are focused on women who are at average risk. are separate guidelines for women who are identified as being high risk of developing breast cancer. And sometimes being high risk is based on carrying a genetic mutation. And so one of the things that we are telling women, if they are wondering what to do, if they receive a letter saying, you know, you have dense breasts,

we are encouraging women to seek breast cancer risk assessment, which is a dedicated visit with someone who will review all of your breast cancer risk factors and may use some breast cancer risk prediction models. And at the end of that consultation, they may refer you for genetic testing for specific mutations. If one of those is identified, there are, you guys,

specific guidelines about how to proceed and what tests might be used from more intensive screening. Now that the guidelines have moved the age back from 50 to 40, are health insurance? And Medicare and Medicaid, are they going to be able to follow these guidelines

and get you covered at an earlier age? There are many organizations that issue breast cancer screening guidelines. The ones from the USPSTF are especially important because they are linked to insurance coverage by the Affordable Care Act, which is also known as the Obamacare Law. This law requires that private insurers cover preventive services that USPSTF gives a grade of A or B without cost sharing to the patient. And that's why these new guidelines,

which gives screening mammography starting at age 40 a grade of B are so important. Because the cancers are starting at earlier ages, I'm curious about why they did not increase the screening rate instead of every other year, perhaps one per year. What's the logic there? That has to do with the focus on balancing benefits and harms. When you move from screening every other year to every year, essentially doubling the number of screening. that you perform, the false alarms increase faster than the additional cancers that you can detect. For some people, that is worth it. And for others, it may not be. And so I will say in our clinical practice, what we recommend is screening at least every two years. We want to communicate

that screening works when we are able to use it regularly. And so we want people to plan to come back regularly, whether at annual or biennial, which is every other. year intervals because that is most important. But we do think it is very important. We support women who make the choice to come back every year and also women who make the choice to come back every other year because it's a better way to balance these benefits and harms. Speaking of the benefits and risks and talking about, you mentioned women in their 40s, are you saying they are more likely to receive a false positive than older women? They are because the age-specific incidence of cancer is lower in women in their 40s.

Can I give you a numerical example of breast cancer screening? Sure, please. We love to deal with the data here. So let's take a hypothetical cohort of 1,000 women, and all of them are receiving screening mammograms. Look into the punchline first. How many women with cancer do you think we will identify? Oh, this is a quiz. This is not good on bad at quizzes.

I'll say five. That's right. That's exactly right. about five to six. So for every thousand women we screen, we'll find five to six cancers. Now, screening mammography is not a definitive test. It does not tell you whether or not you have breast cancer. It tells you whether there's something there that requires additional evaluation. So all those thousand women who just got mammograms, how many do you think we're going to ask to come back for additional evaluation? Let's say 50. I don't know. So about 100. You know,

The recall rate, we call them recalls asking someone to come back. The recall rate, you know, generally runs between 5 and 12 percent, but let's say 10 percent to make it easier. It's 100 women that we are asking to come back for additional evaluation. That is time away from work and family and anxiety that they might have breast cancer, not to mention potentially out-of-pocket costs, but these are going to be removed by the new recommendations. That is good news. Out of those hundred women who are coming back for additional imaging, what they'll do is they'll get special views with the mammogram that focuses on the area of interest. Maybe they'll have an ultrasound as well during the same visit. Then we'll come up with a recommendation. Either we'll say something like,

oh, it turns out to be a benign cyst meets all of our ultrasound criteria. Nothing to worry about. We'll see you next year. Or we might say, you know what? It doesn't meet our criteria for being something benign and that we can tell on this non-invasive imaging we're going to have to do a biopsy. And that is about 20 to 25 women who we're going to ask to come back for a biopsy. And so those 20 to 25 will receive a biopsy and what they had already established, about five to six while cancer. So you can see why this balancing of benefits and harms is so hard. What's your advice to listeners who still feel a bit uncertain about this change?

Maybe they were recently told by their doctor to wait until 50 to start screening, and now they go to their doctor and say, you know, I heard about these new recommendations and their doctor hasn't heard about them or doesn't agree with them? What do you say to these people? Find a new doctor? Well, I would say talk to your doctor. Have a conversation about what they know, you know, what the latest information is,

and particularly because I think so much of this matters about how people feel about balancing benefits and harms, it really matters what the individual women's preferences are. And I think that's what's most important because we want people to come back regularly. You know, if people would prefer to come back every other year but feel a little shy about saying that I don't want them to come have a single screen and not come back. You know, we want to set it up and support it so that they'll come back regularly for screening.

And so that's why we want to support whatever screening plan a woman feels comfortable with. I understand that. One last question, because AI is everywhere now. and I'm wondering how AI might be used to read these scans. Is it being used? Will it be used? Could it find more incidents earlier? What's your take on this?

AI is being used. There are commercially available algorithms that are being used to help with breast cancer detection. Overall, I would say it is a good thing. You know, I am a dedicated breast subspecialist, which means all I do clinically is for breast cancer. There are other radiologists who are more general in what the agency. certainly they're trained to, and they read imaging scans for all sorts of conditions, all sorts of imaging modalities. And AI may be helpful in helping someone who doesn't read

breast imaging all the time be as accurate as someone who does. Now, that being said, you know, every AI algorithm is developed in specific populations, and we want to make sure that as we roll these out, these algorithms are validated. They're tested in other populations to make sure they are as accurate in the populations that they were trained in. One specific example that relates to my own research is women who have a history of treated breast cancer. Here's what there are some changes in the breast related to breast conservation therapy, it's not yet clear whether those changes might be flagged as a false alarm by an AI algorithm

training women that don't have a history of breast cancer. Or if someone has a mastectomy and you have an AI algorithm that is trained using information from two breasts, what does it do with an algorithm that has one? breast but doesn't have the other side to sort of say, oh, is this a symmetric? Is it something that can let go? Might there be a higher false positive rate in that population? You know, we just don't know about specific subpopulations within the larger group. And so additional studies are needed.

You know, when you have an algorithm that is very good at detecting breast cancer, that is really good news. But we want to make sure that it performs equally across an entire population. So another concern is how do algorithms, perform in different race and ethnicity groups. If they are primarily trained in one group, what we want is what we call performance equity. We want the algorithm to be as accurate in specific groups

as it is in the population as a whole. So there are a lot of studies that are going on to do just that to help us apply it more. Well, Dr. Lee, we've run out of time. I want to thank you for being quite informative today. Oh, thank you. Dr. Janie Lee, Director of Breast Imaging at the Fred Hutchinson Cancer Center and the University of Washington School of Medicine in Seattle, Washington.

That's all the time we have for today. Lots of folks help make this show happen, including... Felissa Mayors. Kathleen Davis. Jordan Smudjick. Charles Bergquist. And many more. Tomorrow, dark energy, some new data that, if true, might just upend how we understand

the rules of the universe. I'm sci-fi producer Shoshana Bucksbaum. Catch you next time.