Reducing the Mortality Risk of Breast Cancer (16:11)
83% of breast cancer diagnoses each year are among women aged 50 or older
Broadcast Retirement Network’s Jeffrey Snyder discusses reducing the mortality of breast cancer with Steven Narod, MD, FRCPC, FRSC, Tier I Canada Research Chair in Breast Cancer, University of Toronto.
Jeffrey Snyder, Broadcast Retirement Network
Good morning, welcome back to the broadcast Retirement Network. This is BRN AM for Wednesday, August 14th, 2024. At our top story today, reducing the mortality risk of breast cancer.
Joining me now to discuss this and a lot more, Steven Narod, MD, FRCPC, FRSC, Tier I Canada Research Chair in Breast Cancer, University of Toronto and he’s also the author of The Fair Trial Foundations in Breast Cancer. Stephen, so great to see you. Thanks so much for joining us on the program this morning.
My pleasure. And I’m so happy we could talk about this because I think, I guess I want to start by asking you how prevalent, when you look at society, and of course you’re in Canada, you’re in Toronto, in the States, but when you look at society, how prevalent is breast cancer today?
Steven Narod, MD, FRCPC, FRSC, Tier I Canada Research Chair in Breast Cancer, University of Toronto
Well, it’s the most common cancer in women, about I think 8% of women in Canada will develop breast cancer by the age of 75, so that’s pretty common, it increases somewhat with screening and early detection, but that’s a pretty fair number. It changes around the world, Canada’s one of the higher levels, the United States is about the same. It seems to be less frequent in Asian countries than in Africa.
Jeffrey Snyder, Broadcast Retirement Network
Is there a reason for the frequency differential between, as you mentioned, Africa versus here in the States or in Canada?
Steven Narod, MD, FRCPC, FRSC, Tier I Canada Research Chair in Breast Cancer, University of Toronto
Well, that’s a really important question and there’s various interpretations, but I don’t think there’s any hard facts. I think, you know, some extent we can think of it as the genetic makeup of the population, the risk factors that they are exposed to during their life, but I think also the screening, intensity of screening, increases the frequency. Some cancers that are detected through screening mammography never would become clinically apparent, those are considered over-diagnosis, so the more screening you do, the more cancers you’re likely to identify, and sometimes with little screening you’ll have less cancers than cancers with a lot of screening.
Jeffrey Snyder, Broadcast Retirement Network
Good point, and my apologies, I didn’t mean to interrupt you, sir. And in terms of treatment, how do you typically treat, how does one typically treat breast cancer? I would imagine there’s chemotherapy and there’s several different, probably, protocols you can follow.
Steven Narod, MD, FRCPC, FRSC, Tier I Canada Research Chair in Breast Cancer, University of Toronto
Yeah, well, that’s evolving, but I mean certainly since the 1980s, chemotherapy has been offered to about half, or a little more than half, of women with breast cancer. The mainstay would be surgical treatment, where the surgeon removes the cancer. Sometimes they’ll remove the cancer alone, which we call a lumpectomy or breast conserving surgery.
Sometimes if the cancer’s larger, margins are positive, they’ll remove the breast, we call mastectomy, or you know how to mastectomy, and some people, if they have breast cancer in both sides, or if they have a BRCA1 mutation, or if they’re particularly anxious about a recurrence, we’ll have a bilateral mastectomy. That’s really the patient’s choice, but most women will get a lumpectomy followed by unilateral mastectomy, followed by bilateral mastectomy. A lot will get chemotherapy that depends on the size of the cancer, the nodal status, and then we have anti-hormonal agents, such as tamoxifen, which are given to women with estrogen receptor positive cancers.
The cancer cells show a receptor which indicates that they’re sensitive to estrogen, that the presence of estrogen will likely lead them to grow or metastasize, so we try to block the estrogen with a drug of anti-estrogen. They get tamoxifen, and in some cases we offer actually more extensive hormonal therapy, removing the ovaries altogether. So, instead of blocking the estrogen, we remove the source of the estrogen, which is the ovaries.
There are other types of cancer which there are specialized treatments for, well, personalized treatment. For example, if you have the HER2 gene expressed in the cancer, we use an anti-HER2 treatment, commonly known as Herceptin or Trastuzumab.
Jeffrey Snyder, Broadcast Retirement Network
Steve, you and a team that you led, I think, or at least collaborated with, did a lot of research about what you mentioned, the bilateral mastectomy. Can you tell us a little bit about the research and what the findings were?
Steven Narod, MD, FRCPC, FRSC, Tier I Canada Research Chair in Breast Cancer, University of Toronto
Right. Well, I think about 5% of women who have breast cancer in one breast decide to undergo a bilateral mastectomy, both breasts removed, the breast containing the cancer and the opposite breast. This is done for several reasons.
Some women believe that, you know, the risk of getting a breast cancer in the other breast is substantial. It’s not huge, but it’s about 7% over 20 years. And so, women who wish to avoid that will have sometimes a bilateral mastectomy.
Now, women with cancer in both breasts, it’s a small percentage, will get a bilateral mastectomy as a matter of course. But if they only have breast cancer in one breast, a small proportion will get a bilateral mastectomy. Now, there are several reasons for this.
If you’re going to have breast reconstruction, many times removal of one breast leads to an asymmetric appearance, and the women would rather have both breasts removed and reconstructed in order to have a better body image. That’s a common reason. I think the most common reason is just fear of getting a second cancer, and the ability, if you have a bilateral mastectomy, gives you the opportunity to skip radiotherapy, which is something I did mention, and not necessarily to go for screening every year to see if you have a new breast cancer.
I think a lot of that’s done to relieve stress, anxiety associated with the fear or the concern that you might get a breast cancer in the other breast. But of course, there’s also the question some women, doctors, believe that the bilateral mastectomy, by preventing the second breast cancer, can actually reduce the chance of dying of breast cancer over the long run.
Jeffrey Snyder, Broadcast Retirement Network
And what are the findings? Does it actually help reduce or improve mortality?
Steven Narod, MD, FRCPC, FRSC, Tier I Canada Research Chair in Breast Cancer, University of Toronto
Well, the thing was, surprisingly, we found that if you did get a bilateral or contralateral breast cancer in the other breast, you know, you were more likely to succumb to breast cancer, to die of it. The numbers went up from about 18% to 30%. So, there’s a substantial rise in mortality rate for women who experienced a bilateral breast cancer.
But surprisingly, by doing the bilateral mastectomy, by doing the removal of it, and preventing the second breast cancer, we didn’t reduce the mortality rate. So, the mortality rate in the three groups, chance of dying with a unilateral mastectomy with a lumpectomy, or with a bilateral mastectomy, was about the same over the 20-year period where we followed these women, which is somewhat of a paradox. One would think if the second breast cancer was common enough and had the potential to kill you, that preventing it would be a beneficial option.
Jeffrey Snyder, Broadcast Retirement Network
How do you follow up on this research? Do you continue to follow the same women patients over time? What’s the follow-up to the research?
Steven Narod, MD, FRCPC, FRSC, Tier I Canada Research Chair in Breast Cancer, University of Toronto
Well, I think we have to now explore the biological underpinnings of the observation. The second breast cancer in the other breast looks very much like the first breast cancer, and I think until now, it’s conventionally thought to be a breast cancer in its own right, with the potential to metastasize, and those metastases could eventually lead to the mortality of the woman. But if we find out that removing it and preventing it in the first place doesn’t reduce mortality, we have to question whether this contralateral breast cancer has the potential to metastasize.
So, I think research now should go to try and find out what are the culprit cells, what do they look like, where do they originate, what time are they spread? These are cells that leave from the breast, go to the lung, liver, bone, or brains, and eventually precede the death of the patient. But, you know, it seems we’re challenging the fact that the contralateral breast cancer actually has a capability of generating those cells.
So, where do these cells come from? I’ve actually spent a few years working on this, and not just this paper. This paper is a chapter in my new book, A Fair Trial, The Foundations of Breast Cancer, which goes into that particular question in detail.
This would be one chapter in that book which poses the same question. I think I’ve come to the conclusion that we really know less about breast cancer than we think, in particular the notion of breast cancer spread, or to put it simply, why do some women die of breast cancer and others don’t? So, if people are interested, I encourage them to find the book A Fair Trial.
Jeffrey Snyder, Broadcast Retirement Network
Yeah, absolutely. And Steve, let’s talk a little bit about prevention. You mentioned mammography in the first segment, because it may be different in certain countries versus here in North America.
But how do we prevent, if I have a loved one, a wife, a mother, a sister, a daughter, how do we go about preventing this horrific disease? What can you do to prevent it?
Steven Narod, MD, FRCPC, FRSC, Tier I Canada Research Chair in Breast Cancer, University of Toronto
Well, it’s not horrific in most cases. I mean, certainly in most cases, the women will be cured by the surgery alone. 80% of women who develop breast cancer ultimately survive it.
But, you know, it is still common, and 20% of women with breast cancer don’t survive it. Preventing it, yeah, that’s been a topic of question for many years. There have been, I mean, when we think of the highest risk women, those with the genetic mutation, often they will have a bilateral mastectomy before the onset of the first cancer, and that seems to be quite effective.
But that’s only 4% of breast cancer. The patients will have a mutation, and you have to find that mutation before they develop cancer, in which case I tend to recommend the removal of the breasts with or without reconstructive surgery. Beyond that, there are drugs, for example, tamoxifen, raloxifene, which have been used to prevent cancer, and they do show some benefit.
They’ve been shown to benefit people at high risk who take tamoxifen, who have a lower risk of breast cancer. It goes down by about a third. Surprisingly, to date, we haven’t seen that it reduces the number of deaths from breast cancer.
So, it can prevent cancer, but not deaths from breast cancer. I think one thing that’s important to keep in mind is to distinguish between breast cancer and deaths from breast cancer. Most cancers don’t result in the death of the patient, and I think they have fundamentally different characteristics from the onset, and that not every cancer has the capacity to metastasize.
You know, it’s interesting that the National Cancer Institute defines cancer as cells which have the capability of unrestricted growth and metastases. But many breast cancers, as far as I can see, inherently don’t have the capacity to metastasize, and therefore wouldn’t be considered cancer by that conventional nomenclature. Other ways to prevent it— assuming people have proposed lifestyle changes, in particular alcohol, there has been shown to be an increased risk of breast cancer with alcohol consumption, maybe seven days a week.
But whether or not that’s proven to be a viable strategy to prevent breast cancer in a large population is unknown. I don’t know if women are, at this point, choosing not to have a second glass of wine because their concerns about breast cancer. There have been dietary studies which have been largely negative.
There are studies of taking vitamin D, etc., but they haven’t proven to be as helpful as we have hoped.
Jeffrey Snyder, Broadcast Retirement Network
And lastly, Steve, in terms of detection, so is it still the mammography that’s the best way to detect it? You get a mammogram on a periodic basis. Is it annually?
Is it semi-annually? Or every two years? Is that still the best way to detect this cancer?
Steven Narod, MD, FRCPC, FRSC, Tier I Canada Research Chair in Breast Cancer, University of Toronto
Well, the best way to detect the cancer is actually MRI, magnetic resonance imaging, which is a more invasive procedure. It does take a longer time. It’s more expensive.
So magnetic resonance imaging is more sensitive, picks up more cancers, is really restricted to those women who have a high risk like a mutation. So mammography is a standard of care, which is basically recommended to all women at over, some places over 40, some places over 50. There is certainly a lot of support for the mammography standard for doing this, and some would argue to do it every six months.
Some would argue to do it every year. Some less frequency. The big question now is do we start at age 40 or do we start at age 50?
Yeah, well, the great majority of people are really steadfast believers that mammography is beneficial. I have questioned that position, and I go into detail in that in my book, A Fair Trial, which is really discussing some of the findings of our Canadian study of mammography, where we randomized 90,000 women. The mammograms or no mammograms, and we didn’t find the difference of 30 years in the number of death from breast cancer.
But, you know, that’s a very, that issue is really still ongoing, although certainly majority of cancer agency surgeons, physicians are supportive of endometriography, mostly from age 40.
Jeffrey Snyder, Broadcast Retirement Network
Yeah, well, I mean, it’s certainly, as you said, it’s not a horrific disease in that most people will be cured. But obviously, if you detect it early, and you have the right lifestyle behaviors, and you modify your lifestyle, you’re probably going to, your survivability and your detection in advance is probably going to go up. Steve, we’re going to have to leave it there.
Thank you so much for joining us, and we look forward to having you back on the program again very soon. Thank you, Jeff. That wraps up this episode of BRNAM.
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