The Decibel - The controversy over lowering the age of breast cancer screening

Episode Date: October 17, 2023

In Canada, 1 in 8 women will be diagnosed with breast cancer in their lifetime. It’s the second leading cause of death from cancer in Canadian women and second most common cancer in the country. Currently, guidelines say that screening should begin at the age of 50, but the task force in charge of these recommendations might lower the age to 40. And that has re-ignited a heated debate. Carly Weeks is the Globe’s health reporter. She’s on the show to explain why there’s advocates for and against this change – why some see it as a way to save more lives and others see it as causing more harm than good. Questions? Comments? Ideas? Email us at [e-mail] 

Breast cancer is the second most common cancer in Canada, and it's recommended that screening for the disease begins at age 50. But a task force that looks into preventative healthcare measures is considering lowering the age to 40. And that news has ignited a heated debate. Carly Weeks is the Globe's health reporter. She's here to explain why lowering the recommended age is so contentious. I'm Mainika Raman-Wilms, and this is The Decibel from The Globe and Mail.

Carly, thanks so much for being here today. Of course, anytime. I'd like to just start with knowing what the current recommendations are. So in Canada, what are the recommendations for breast cancer screening? So for women who are sort of considered average risk, not in a high risk category, the recommendation is to undergo mammography screening every two to three years from the age starting at 50 until around 74. We're talking about mammograms

specifically. It's sort of a low dose x-ray that gives a visual of the inside of the breast and what's going on in there to try and help detect the presence of small tumors that wouldn't be able to be necessarily felt. Basically, it's a form of early detection. So before you can feel something in your breast, the idea is catch it and treat it earlier. Okay. And you said this is for the general population then, right? So if you're high risk, this does not apply to you then? Yeah, that's right.

So if you're aware of something that would put you at higher risk, so for instance, if you know that you have a family history of breast cancer or if you have a genetic mutation, you're aware of a genetic mutation that would put you at risk, you're in a different risk category. And that's something where you're going to likely be getting screened more often or starting at an earlier age. Okay, makes sense. And when were these recommendations last updated? They were updated five years ago. So they're currently undergoing a regularly scheduled update just to take into account new evidence and things like that. And so this is a really hotly anticipated update that's coming in the next few weeks. Okay, so we know that breast

cancer is a very common form of cancer. In Canada, one in eight women will be diagnosed in their lifetime. But Carly, who is generally at risk here? Like what age are we talking about? We know, of course, breast cancer is the second most common cancer in Canada. But the risks start to really go up the older that you get. So according to the federal government, 83% of cases occur in women 50 years of age and older. So just to give an indication, this is primarily a disease of middle age and sort of as you get into those senior years. There are cases of breast cancer that are diagnosed earlier, people in their 30s, people in their 40s. And that's what we're really talking about today is a lot of women in their 40s.

There's a contentious debate going on right now as to whether or not there's enough breast cancer incidents happening in that age group to make the screening age lower, or if we need to focus on some of those more advanced stages where we know that there's going to be more cancer detected. Okay, so Canada is now looking at potentially updating the recommendations, the guidelines for screening. This falls to the Canadian Task Force of Preventative Care. This is the group that's looking at this. So let's just start by talking about what is this task force? What do they do? So this is a task force made up of

a variety of different medical professionals, people with sort of health and medical backgrounds who come together to make different recommendations for screening for all kinds of different diseases. But they're basically experts who are coming together to look at all of the available evidence to help make an informed decision for a particular kind of cancer, whether it be cervical cancer screening or another type of health preventive measure. Okay. So this task force is now looking at updating the breast cancer screening guidelines. What is behind the push to look at this now? Right. So this is a regularly scheduled update, but, you know, and that's a big but, there's been a huge, you know, amount of debate over this in the ensuing years. So as soon as the guidelines came out, there were a lot of

people in the breast cancer advocacy community in Canada saying that this is a mistake, that, you know, the guidelines should start screening at the age of 40 to save more lives. What's happened since then, earlier this year, the United States Task Force on Preventive Healthcare came out with their own draft recommendation saying that women should start breast cancer screening at the age of 40 because they're noting an increased incidence in breast cancer in women who are in their 40s in the last number of years. And so they're saying, look, something is going on here. We should expand screening out to catch more cancers. So that draft recommendation came out in May. So we're talking not that long ago.

When that decision came out, it really sparked a huge outpouring from the advocacy community here, sort of demanding on the Canadian task force to make a similar recommendation. And we got to the point where the federal health minister chimed in. So the federal government has chipped in $500,000 to the task force to expedite the publication of these guidelines, kind of recognizing the fact that there's so many people who are really invested in this outcome. Okay. Let's talk about the evidence that they were looking at in the U.S. So you said something about how they were seeing more incidents of breast cancer in women in their 40s. But what was the actual data, I guess, that was backing that up?

One of the main changes that they cite for making this recommendation is what they said was an increased incidence of around 2% new cases per year in women in their 40s. So basically, there's noting a rise, an unexpected rise in breast cancer cases diagnosed in women in their 40s, particularly from 2015 to 2019. And sort of using that logic, saying, well, then we anticipate that there's something going on here, so we should be doing more screening to catch those cases. Okay. that there's something going on here. So we should be doing more screening to catch those cases. Okay. And so if we're looking at that data then, so is, I mean, it sounds like a good thing,

right? You're going to catch cancer earlier. I guess what, you know, what is the controversy here? And this is, I think, where a lot of the debate is. You know, there's people who would say, look at the evidence. We are, you know are catching more cases of cancer. We're saving more lives. Mammography works, and it's a slam dunk. On the flip side, and this is really important, incidence data doesn't necessarily tell you the whole story. The incidence data of breast cancer, according to some who work in the field, is a very flawed metric that we shouldn't really look to to understand the benefits of mammography. And when you say incidence data, this is like the number of people with cancer? Is that what that would be? Exactly, the number of people who are diagnosed.

So in a given year, we see X thousand people diagnosed with cancer. What a lot of people say we really need to look to is the mortality data. When you're looking at incidence data, there could be cases of missed cancer. There could be cases of cancer that was overdiagnosed, so a case of cancer that might not ever become symptomatic that is diagnosed. So in some ways it can be misleading, whereas mortality data is very final. It's not really something that you can escape from. So for many reasons, mortality data is seen as more reliable by people who work in this field. There was a paper published in the New England Journal of Medicine last month that looked at mortality outcomes for

people in their 40s who had been diagnosed with breast cancer who had either been screened or had not been screened. What they found is that countries that did not have organized screening programs for women in their 40s, namely Switzerland and Denmark, had lower mortality breast cancer rates for women in their 40s compared to the United States, where 60% of women in their 40s are already screened for breast cancer. It doesn't seem to make sense on its face.

Why would mortality be lower in countries that don't regularly screen women in their 40s? And then we start to look at what access women have to treatment options, to new advances in medicine. That is where a lot of the improvements in breast cancer mortality have come in recent years and decades is huge advances in medicine that are allowing women to live longer, to get a devastating diagnosis and end up living because of the advances that we have in treatment. So it's not really the screening. If you look at these numbers, this is not the screening making the difference. It's the medicine making the difference. Wow. Okay. Yeah. This is kind of a different thing than I think a lot of us are used to hearing, right? Because we're always used to hearing about the importance of screening, but this is actually looking at the effect that medicine

and the other aspects of the healthcare system that can actually help improve your mortality rate there. Yes. What do we know about Canada, Carly? So we're talking about the U.S. and how they were seeing higher numbers of cancer in women in their 40s. Do we know if that is the same in Canada when it comes to women in their 40s? Are we also seeing that uptick in the number of cancer cases? Yeah, actually, I asked Statistics Canada for as much data as they could have, you know, going back a couple of decades on incidents.

And the incidence data for women in their 40s has remained pretty stable in the last number of years. But more tellingly, I think, is the mortality data. And we've seen a pretty significant drop in mortality for women in their 40s. So for instance, just to pull out a couple of numbers, the mortality rate for women and actually sorry individuals, it's counting both men and women who are 40 to 49, mortality rate was 12.3 per 100,000 in the year 2000 and by 2021 it had dropped to 8.1 per 100,000. People in their 40s, there were 317 breast cancer deaths in 2021. For people in their 60s in 2021, there was 1,121 deaths. Just to give context for the scope and scale and how much the risk starts to go up with time and why some people argue that we should really focus more of our screening efforts on people who are sort of in their 50s and 60s and beyond.

We'll be back in a moment. Maybe we can take a moment here and just look at some of the history here as well, Carly. So how far have we actually come when it comes to screening for breast cancer? Yeah, so mammography has been around for decades. It was sort of invented early in the 1900s as a way to kind of understand, can we detect what's going on in the breast and diagnose a problem before it becomes sort of physically manifesting itself in symptoms? And so that became a test that was used, you know, throughout sort of the 1900s, 1950s onward, really heavily seen as a way to help, you know, save lives, help detect cancer early. And then in the 1980s and 90s, there were some randomized control trials that were done. So randomized control trials are seen as the gold standard because there's,

you know, essentially two different control groups in the study. There's like the treatment group, and then there's the people who are not getting the treatment. So people who are being screened, people who are not getting screened, and then sort of looking at what happened since then. And some of those studies, the seminal ones were done in Canada, and they cast a bit of doubt or a lot of doubt on the benefits of screening mammography, essentially saying that, you know, the benefits are being overblown, that in fact, this may not save the lives that we think it saved. And that led to, I think, what we are continuing to live through right now is a period of pushback on the mammogram saying that, you know, maybe not all women should be getting them and they

should be focused on a subset of women who are in a certain age category or risk category. And I think that that culminated in the 2018 guidelines. And when those came out, you know, they were very controversial. There was a huge amount of pushback from the breast cancer community, a lot of people saying that this is very harmful and damaging. And I recall that I covered that at the time. And the outpouring, it's really sort of hard to overstate just how much upset there was in the community at that time. And it kind of, and since then, what's happened is there's been a lot of pushback on those studies that were done in the 80s and 90s, saying that they used flawed methods, that these studies were not reliable, that in fact, newer studies are showing mammograms are

more helpful. To say that it's very contentious and it's very hard to wade through conflicting evidence is, yeah, a bit of an understatement. So the task force has a huge job on its hands to try and wade through a lot of this. Yeah. And it sounds like a lot of this does center around mammograms, right? And how effective they are. And you mentioned how in the 2018 guidelines, this was a big thing. Also in the 2018 guidelines, one of the takeaways is that doctors should inform patients of the potential risks of mammograms. So what are the potential risks of mammograms? The argument against the mammogram that a lot of people make is that it's not this sort of risk-free procedure. I mean, yes, it's a low-dose x-ray and it's relatively cost-effective and

those kinds of things, but it can expose people to unnecessary harm. So if you look at the United States guidelines, they use some sort of sophisticated modeling to try and predict, you know, how many lives mammograms could save. Using their own modeling, you know, nearly 40% of women who are in their 40s will receive a false positive result, you know, in a 10-year period. 40%. It's a huge number. I mean, in their model, it's 36%. Now, that's hard to say how that manifests in the real world, but we know that part of the harm is just the anxiety and the fear of being told that you may have cancer and then having to wait, you know, potentially weeks or longer for a follow-up test to tell you whether or not you have cancer.

Some research has found that people who are in that waiting period report having sort of the most, you know, stress that they've had in their lives. We also know that the anxiety or the fear is not the only harm. So, you know, as soon as you start to screen women, you also increase the risk of unnecessary invasive tests like biopsies. So again, going back to this US modeling that they used to lower their screening recommendation, their own modeling shows that nearly 7% of women will have a false alarm that requires a biopsy unnecessarily. So that's a painful procedure. Again, like leading you down this road into interventions and treatments that were necessary. There's also very strong evidence to show that a certain percentage of women who are screened in their 40s will be diagnosed with cancer that would never have become symptomatic.

And this is another very controversial area of medicine. And it just goes to show you, I think, how complicated this area is, how fraught it is. And going back to what the Canadian guidelines really emphasized in 2018 was for the individual to have the conversation with the health care practitioner. And I hear all these things that you're saying, but I think I still wonder, and I think a lot of people still wonder, right? We're talking about the fear and the anxiety and the invasiveness of the biopsy, but don't all of those things pale in comparison to the prospect of missing a breast cancer diagnosis? Wouldn't you rather be, I guess, over-screened instead of

potentially missing something that could be life-saving? This is the crux of the argument right here. And I think that when you talk about the idea of a missed cancer, I think it does strike fear into the hearts of everyone. And it sort of makes you think, well, I think whatever the harms are, then obviously the benefits are worth it. But I think when you look at the totality of evidence, for instance, in order to save the life of one person with screening mammography, you would need to screen 1000 people every year for 10 years. And I think that when you start to look at all of those numbers and put them into context, I think that's where people then start to go on their own individual decisions. To some people, that number would say, well, for every, you know, 1,000 people screened, saving one life over 10 years is worth

it. I want to be that person. I want to get screened. Someone else may say, no thanks. I would rather, you know, look at what other, the evidence is strongly in favor of, which is saying, be aware of any changes in your breast. talk to a healthcare provider. I mean, it does seem as though we're at a stage in Canada where, you know, breast cancer mortality rates have been dropping so steadily. But, you know, we need to maybe focus more on helping improve outcomes for people who tend to be more disadvantaged or address the fact that some people may not have a primary care provider. So if they see a change in their breast, who are they going to take that to?

I also want to ask you about race and all of this, Carly, because advocates of lowering the screening age to 40 have also been concerned about the outdated data not taking into account how this disease shows up in people of color, right? So this is something that the U.S. task force highlights on their website. They say that black women are 40% more likely

to die from breast cancer than white women. So, I mean, isn't that a strong argument to have a lower age for screening? It sounds like one. So I interviewed the author of this New England Journal of Medicine paper that came out in September. And I asked him this very question, you know, if we're knowing that the outcomes are so much worse for black women, don't we need to be focused more on screening that population and sending home messages about that? So he actually looked at the data and what that data shows using the same U.S. Task Force data is that black women are much more likely to be diagnosed with a certain rare type or relatively rare type of aggressive cancer, triple negative breast cancer that tends to not be very responsive to available treatments. So black women are much more likely to be diagnosed with this and die as a result. But in fact, if you look at the screening data, they're just as likely to undergo screening as white women who are sort of in that same age category. So in this situation, it's not clear

at all how more screening would help this group. And it really starts to be, you know, it sounds very compelling to instead look at how do we help improve treatment for this type of cancer to improve health outcomes. And, you know, I think we see that manifest in Canada as well. Obviously, our population is different. But we do know that people who are racialized, people who are indigenous, people who live in rural and remote areas have worse health outcomes. Now, is that because they didn't have access to a mammogram? Or is that because they don't have a family care provider? Is that because they live in an area where they don't have access to the system, where they don't have a health provider who speaks their language, where they don't trust the healthcare system? I

mean, there's so many different barriers that stand in the way of people accessing the care that they need to improve those outcomes. And it's not as clear that, you know, just a blanket policy advocating for mammograms for all in their 40s is going to do much of anything to move those numbers where we want them to be, which is even lower. Well, Carly, thank you so much for taking the time to explain all this today. Thanks for having me. That's it for today.

I'm Mainika Raman-Wellms. Our producers are Madeline White, Cheryl Sutherland, and Rachel Levy-McLaughlin. David Crosby edits the show. Adrienne Chung is our senior producer, and Angela Pachenza is our executive editor. Thanks so much for listening,

and I'll talk to you tomorrow.