Evidence of meeting #94 for Health in the 44th Parliament, 1st Session. (The original version is on Parliament’s site, as are the minutes.) The winning word was risk.
A video is available from Parliament.
NDP
Don Davies NDP Vancouver Kingsway, BC
Dr. Wilkinson, to your understanding, why did the U.S. change its guideline and lower the screening age from 50 to 40?
Doctor of Medicine, As an Individual
The U.S. assumed a benefit of screening, so they did not review evidence before 2016. They moved on. They found no new randomized control trials, much like we spoke to. These trials were all or primarily done a long time ago.
They assumed benefit and they had to look at other things. They looked at some non-randomized trials. They also looked at some modelling data, because we know that we cannot rely on the old trials. The old trials were done before digital mammography. They were done even before tamoxifen existed. We are talking about very rudimentary treatment.
These old trials only show a mortality benefit of 15%, compared to the 40% or 44% that we're hearing.
The other thing the U.S. looked at was the impact on minority groups and the younger age at diagnosis for Black and Asian women. The increasing incidence, the change in the different age of diagnosis and the modelling data are what prompted the change.
Liberal
The Chair Liberal Sean Casey
Thank you, Dr. Wilkinson.
I'm sorry, Mr. Davies. That's your time.
Mrs. Roberts, go ahead, please, for five minutes.
Conservative
Anna Roberts Conservative King—Vaughan, ON
Thank you, Mr. Chair.
I want to state a quote I found at the Public Health Agency of Canada. The “breast cancer death rate peaked in 1986 and has [declined] since.” However, there has been a reduction in death rates due to “the impact of screening and improvements in treatment for breast cancer”. That's according to the Public Health Agency of Canada.
My question is going to be for you, Dr. Anna. I love your name.
You have been a supporter of organized screening for women under the age of 50. You have noted that, “There is a significant increase in survival for women if they live in a province with an organized screening program with self-referral and annual recall for women in their 40s”. You also mention that 16% of breast cancer occurs in women between 40 and 50 years of age.
Can you please help us understand the importance of screening? I know that you're an advocate of it. I really appreciate that as a woman, because I think we need to make sure that women deserve to live and deserve to have the screening. Without us, they wouldn't be here. Let's be honest.
I really love what you're saying and I love what Dr. Gordon is saying. I think you guys are on the same path. Could you please elaborate on why we can save more women if we implement more screening at an earlier age?
December 6th, 2023 / 8:35 p.m.
Doctor of Medicine, As an Individual
What screening does is it diagnoses cancers earlier. Screen-detected cancers are often only four millimetres wide. They're cancers that are detected before you can feel them. Smaller cancers, by definition, are at an earlier stage. Earlier-stage cancers, by definition, have better outcomes and less-intensive treatments.
In terms of why you should have an organized program, if that screening happens within an organized program, that means that a woman can self-refer. This is key in this day and age, where a lot of women do not have access to a family doctor or where a family doctor may be a barrier to screening. The family doctor is hearing that the task force says, “Don't screen.” The woman comes and says, “Can I be screened?” and the doctor says, “You don't need to be.”
Women in organized programs get recalls. We're all busy. Life gets a hold of you. The program sends you a letter and says to remember to come for your mammogram this year.
There are quality controls within organized screening programs as well. There are metrics that are followed in terms of the quality of mammograms, reading, follow-up and all of those issues. That's why organized programs are so key. With our current national guidelines, there are no organized programs for women in their forties across the country. It is completely dependent on the province you live in.
Conservative
Anna Roberts Conservative King—Vaughan, ON
I forgot to mention this earlier. I want to thank you for sitting with patients. I've done it as a volunteer in the long-term care home. It really makes a difference to the patient. Thank you for doing that.
My other question is for you or Dr. Gordon.
Do we need to do a study on the creation of guidelines by the Canadian Task Force on Preventive Health Care for women, so that we can start fresh by discovering that we can save more women? Maybe we need to start now and start doing it for all women, regardless of race.
Doctor of Medicine, As an Individual
Our task force has been looked at as the gold standard. Why is it the gold standard if experts don't agree with the guidelines? Why is it the gold standard if provinces are doing their own thing and not doing what the guidelines are saying?
The reach of the task force and their guidelines is very broad and hits many points of women's health. It includes lung cancer screening and cervical screening. The last time the cervical guidelines were updated was 10 years ago. In the interim, the whole world has moved to HPV-based screening. That's where we should be. We are handcuffed back to 10 years ago with the old guidelines.
There are other examples of guidelines. Our guidelines tell us not to screen for postpartum depression. We are one of the only countries in the world that suggests that. There are many issues with guidelines across—
Conservative
Anna Roberts Conservative King—Vaughan, ON
I just quickly want to thank you and Dr. Gordon. I think that you do women justice. Thank you for making sure you protect us. There aren't too many people—
Liberal
The Chair Liberal Sean Casey
No, I'm afraid you can't, Dr. Gordon. We're at time.
If Mrs. Atwin wants to give you some of her time, that's up to her. The floor is for Mrs. Atwin for the next five minutes.
Liberal
Jenica Atwin Liberal Fredericton, NB
Thank you, Mr. Chair.
Thank you very much to our witnesses for being with us this evening.
Even just this evening I've learned so much, to be honest. I didn't realize how many different veins my mind would be going in with this kind of a conversation. I think about conversations I've had with my mother about getting tested and the unpleasantness around getting a mammogram but also how important it is. Also there's the general sentiment in my circle of friends. We're all entering that stage where we should be looking at getting screenings.
There's the importance of self-checking. I see in the 2018 guidelines that they're actually recommending against the practice of breast self-examination for screening for breast cancer. There are a few other concerning things in the 2018 guidelines. There are also pieces about the potential for false positives or overdiagnosis, which has very much piqued my curiosity. I've never been warned about the potentials or risks there.
To any one of our witnesses, would you like to jump in on that piece? Could you just clarify for me what the risks are for overdiagnosis or false positives?
Doctor, Dense Breasts Canada
I'm happy to do that.
First of all, even the term “false positive” is pejorative. It's really fearmongering, because we're not telling women they have cancer when they don't. What they use the term “false positive” to mean is a false alarm, where something showed up on your mammogram and at the end of the day it's probably not going to be cancer, but it deserves another look. For women who have anything that's out of place or that needs more testing—sometimes it's just another couple of mammogram pictures—they are recalled.
That's what it should be: a recall or a false alarm. With the majority of women, we can sort it out with ultrasounds or mammograms. If you take the real numbers in this country, out of every thousand women who are screened, 70 will be recalled, and of those 70, 11 of them—so now we're talking about 11 out of the thousand—will be told that they should have a needle biopsy.
I must tell you that a needle biopsy is done with adequate local freezing, and most women say it's no more uncomfortable than a blood test from the arm. I know that no one believes me when I say that, but the best comment I ever heard from a patient was, “Dr. Gordon, I have shoes that are more uncomfortable than this test.”
In any case, out of the 11 who have a needle biopsy, four of them are told that they have cancer. For the 11 women going through this test, the task force calls them “unnecessary” tests. Well, it's not an unnecessary test until you find the answer. Most women would rather go through something relatively painless to be more sure that they don't have cancer.
That's the false alarm story.
Overdiagnosis is a little tougher to explain. Overdiagnosis is when we find a cancer and it's a real cancer, but that cancer would not have killed the patient had it been left untreated. The typical scenario is that, if we're dealing with an elderly woman and we find a small cancer, it may not be problematic for five or 10 years, but she's also got lung cancer because she's older and she's at higher risk for lung cancer. That lung cancer is going to kill her before her breast cancer would.
Here's another example. A woman gets diagnosed with cancer, she gets treated, she finishes all her treatment and two weeks later she gets hit by a car and dies. That's actually overdiagnosis, because that cancer wasn't going to kill her, but unless you have a crystal ball and you know that you're not going to have a fatal heart attack or be hit by a car, every woman with a new diagnosis of cancer is offered treatment.
It's estimating overdiagnosis that's tricky. The task force used an estimate of 48%. They said that almost half of cancers are overdiagnosed, meaning that they shouldn't have been found or treated. That's because they got that data from that flawed Canadian trial that we heard about from Dr. Narod, and that's why there was no difference in the death rate and all their stats are off. International experts believe that overdiagnosis occurs in about 1% to 10% of women, and probably at the lower end of that range. Now remember that these are real cancers. It's just a question of whether that cancer is going to kill the woman.
Most importantly, our task force is using overdiagnosis as a reason to not screen women in their forties. Women in their forties are much less likely to have a competing cause of death and overdiagnosis in that age group is negligible, so it's absolutely not a reason to not screen women. When it comes to false alarms, we should not only be telling women about overdiagnosis and false alarms but also letting them know there's a possibility that they'll be recalled and mostly it turns out to be nothing.
It's condescending for the task force to decide on behalf of women that they're too fragile to handle a little transient anxiety. Women should be able to decide for themselves. If they say, “No, it would ruin my life and I'd rather risk getting cancer”, that's a woman's choice. Most women, when they understand the principles of overdiagnosis and false alarms, would like to be screened.
Liberal
The Chair Liberal Sean Casey
Thank you, Dr. Gordon.
Ms. Larouche, you now have the floor for two and a half minutes.
Bloc
Andréanne Larouche Bloc Shefford, QC
Thank you very much, Mr. Chair.
I'm going to continue along the same lines as my colleague Ms. Atwin.
Since the beginning of the meeting, we've been asking a lot of questions about the prevention of these cancers. One of the counter‑arguments is that there are false positives or overdiagnosis.
Dr. Gordon, you explained the difference between a false positive and overdiagnosis. What are the real risks of overdiagnosis? Is it the mental health effects on women or the side effects of treatment? Is it because doctors, specialists or rooms are being removed from other prevention cases and other treatments? What are the real criticisms of overdiagnosis and what are the real risks for women, other than mental health? That said, if you want to address the issue of mental health, please go ahead.
Doctor, Dense Breasts Canada
The problem is that we don't know at the time we diagnose a cancer whether it is overdiagnosed, because we don't know yet when that woman is going to die. Now, you could argue for example—you heard this earlier—that if a woman is in good health and she has a life expectancy of at least seven to 10 years, then we should keep screening her. It's when women are ill with other potentially deadly illnesses that they can stop having mammograms. If they have end-stage heart disease or end-stage renal failure and they're not likely to live 10 more years, then let's not go looking for a cancer that will not be threatening to them before their other illness will kill them.
It's a question of judgment. There's no harm in diagnosis. We don't know and that woman deserves treatment, because she might live another 20 or 30 years. It's more a question of judgment as to when to stop screening.
Many of the screening programs stop at age 74. If a woman wants to continue screening then she needs a requisition from her doctor. There are several provinces that allow women to keep self-referring. That assumes that they're in good health with a reasonable life expectancy.
Liberal
The Chair Liberal Sean Casey
Thank you, Dr. Gordon.
Next is Mr. Davies, please, for two and a half minutes.
NDP
Don Davies NDP Vancouver Kingsway, BC
Dr. Gordon, I want to make sure I have this right. The current task force has recommended against screening until women are 50 for about the last 10 years. If I am hearing the evidence right, the criticisms of this are the following: They're basing that on outdated evidence being used, the diminishment or ignoring of current evidence, a lack of expert input or subject matter expertise, and the potential bias of task force members.
Would that be an accurate summary of the concerns?
NDP
Don Davies NDP Vancouver Kingsway, BC
Dr. Wilkinson, you've mentioned the need for transparent processes. Can you elaborate on your experience as a member of the evidence review committee?
Doctor of Medicine, As an Individual
I can only elaborate on what I've experienced. Certainly, I've not seen transparency to date.
Our recommendation was to not use old data as the expert. However, during the time that we were trying to establish the evidence base, it seems that the working group was already working on evidence—although I don't know where it came from, since we had not completed our review. When we went to finalize things and there was all of the old data included in the evidence, we were told this was because the task force had demanded that this evidence be included.
I asked where the overdiagnosis number was coming from, because this is a key number. If you say, as we said earlier, that the overdiagnosis rate is 50%, what that means is that, if you're using an old trial with the benefit of 15% and you say that 50% of those don't matter, then you're down to 7%. If you take the newer trials at 40% benefit and you say there's zero overdiagnosis, then you have a 40% benefit. The evidence review panel did not know where that number came from. That is not a number that they were supplying to the task force working group.
NDP
Don Davies NDP Vancouver Kingsway, BC
Thanks.
Ms. Dale, I just want you to jump in a little bit.
You have talked about the current patchwork of breast screening practices across the country. How does that impact Canadian women's abilities to get the care they need?
Co-founder and Executive Director, Dense Breasts Canada
It impacts it significantly.
We look at provinces. Dense Breasts Canada compares all of the provinces in terms of optimal breast cancer practices. We looked at five different key practices. You have a province like Quebec that scores zero out of five. Then you have a province like Nova Scotia that scores five. Most of them score two out of five. That means that women in a province like Quebec do not have equal access to finding cancer early. It's a postal code lottery. We want to see all women in Canada have the same access for that.
We found that, even in provinces that do self-refer at 40, the family doctors are still dissuading women from getting screened. The task force guidelines are still playing a key role, regardless of self-referral. We're also finding with this inequality that there's confusion across the country. We did a survey of 2,500 women and 42% of them did not know what age screening began in their province.
Beyond the confusion, we also have women on social media all of the time—
Liberal
The Chair Liberal Sean Casey
Thank you, Ms. Dale. I let you go a little longer because it was the first question you got on this panel. We are well over time.
Dr. Kitchen is next for five minutes, please.