The truth behind breast cancer screening claims

cancer, protein
Reading Time: 4 minutes

Misinformation about breast cancer screening – mammograms – still a problem

Alan CasselsI was about to call it a day when an email arrived with the following in the subject line: “The Best Health Advice You’ll Get Today.” That caught my attention.

I was curious. And I’m a sucker for free health advice. I’ve got more than just a passing interest in health advice, seeing as I spend much of my working hours examining the quality of evidence that underlies what people say about drugs, screening and other kinds of health treatments. So when someone wants to offer me the ‘best,’ I sit up and pay attention.

I quickly learned this email was sent to me from the Canadian Breast Cancer Foundation as part of their monthly update. The email was essentially reminding me about how important breast cancer screening is and how often women should subject themselves to it.

breast cancer protein mammograms
Related Stories
Flawed breast screening studies may have led to death of thousands


Discovery may improve understanding of how breast cancer spreads


New way identified to prevent breast cancer cells from evading therapy


“Mammograms save lives” read the headline. My heart sank. Not only is this headline unlikely to be true, it’s possibly dangerous. The headline followed with the statistic that “regular mammograms for women age 40 and over equal a 25 percent reduction in the number of breast cancer-related deaths.”

Many scientists who have looked closely at the evidence have soundly questioned routine mammograms for healthy women (those with no extra risk factors for the disease), and particularly for younger women (those between ages 40 and 59) because of the very real problems of overdiagnosis and overtreatment. So why is an organization dedicated to this serious condition sending out such misinformation – and why now, I wondered? Because, as the email says: “There appears to be much information of late in popular media about who should go [for screening] and how often.”

In other words, perhaps they felt it was time to counter what the scientists were saying. It was three years ago in the Canadian Medical Association Journal when Danish screening expert Dr. Peter Gotzsche asked a provocative question: Which country was going to be the first one to stop mammography? He was also the lead author of a Cochrane Review of mammography which included seven trials involving 600,000 women between 39 to 74 yearsrandomly assigned to receive screening mammograms or not and found that the screening did not reduce breast cancer deaths.

Then last February, a 25-year study by Cornelia Baines and Anthony Miller at the Dalla Lana School of Public Health in Toronto added weight to that assessment, finding that annual breast cancer screening of women age 40 and 59 does not reduce breast cancer death rates compared to regular physical examination or usual care. This message got a fair bit of media play because it was, after all, a Canadian study and one of the biggest and highest quality studies ever done on breast cancer screening.

This research is adding up to what I would call a wholesale re-questioning of the need for mammography based on the fact that the overall benefits seem to be vanishingly small and the harms – including unnecessary cancer scares, biopsies and surgeries — considerable.

Just two weeks ago, an article from the New England Journal of Medicine was published suggesting that Switzerland might be the first nation in the world to dismantle its breast cancer screening program for women of average risk. In a report prepared by the Swiss Medical Board (a group that assesses medical technology), the authors wrote that mammography screening of women between 50 and 69 may prevent one breast cancer death out of a 1,000 screened women, but that there was no proof that screening programs affect overall deaths. In other words, echoing the work of scientists like Baines, Miller and Gotzsche, the mantra that “Mammography Saves Lives” is simply not true for most women.

The authors of that recent New England article concluded by saying: “It is easy to promote mammography screening if the majority of women believe that it prevents or reduces the risk of getting breast cancer and saves many lives through early detection of aggressive tumours. We would be in favour of mammography screening if these beliefs were valid. Unfortunately, they are not, and we believe that women need to be told so.”

But what do Canadians get instead?

The Canadian Breast Cancer Foundation saying we should ignore the science, as they dish out the “Best Health Advice” via an email on a Friday afternoon.

Alan Cassels is a pharmaceutical policy researcher and the author of Seeking Sickness: Medical Screening and the Misguided Hunt for Disease, which has an entire chapter devoted to the breast cancer screening debate.

For interview requests, click here.


The opinions expressed by our columnists and contributors are theirs alone and do not inherently or expressly reflect the views of our publication.

© Troy Media
Troy Media is an editorial content provider to media outlets and its own hosted community news outlets across Canada.

By Alan Cassels

Alan Cassels is a drug policy researcher affiliated with the School of Health Information Sciences at the University of Victoria. He has worked on a variety of research and evaluation studies for the past ten years focusing on the impact of provincial drug benefits policies on consumers and has specialized in examining how clinical research information and experience on drugs gets communicated to policy-makers, prescribers and consumers.

10 comments

  1. Mr. Cassels, a pharmaceutical policy
    researcher, has weighed in on screening mammography. He does women a
    disservice. He quotes only the 25-year update of the Canadian National Breast
    Screening trial, and does not include the fact that this was the ONLY trial of
    mammography screening that didn’t show decreased mortality. It is an outlier,
    and in 2002, the World Health Organization determined that it should be
    disregarded in in future considerations of the benefit of
    mammography. The flaws in the Canadian trial have been documented ad nauseum. But
    every 5 years they publish an update and cause a media frenzy and confusion for
    women.
    When the results of better trials are
    averaged, women invited to have mammography showed reduced death from breast
    cancer of 25-30%. More importantly, in women who actually have mammograms (many
    women invited in trials do not, but are still counted in the mammogram group
    when deaths are counted!) the mortality reduction is in the 40-50% range.
     But Mr. Cassels, whose declared conflict of
    interest is in selling his anti-screening book, says that promoting mammography
    is possibly dangerous. He quotes the harms of overdiagnosis and overtreatment,
    and cites Dr. Peter Gotschze and the Cochrane review, which have been roundly
    criticized by authorities in public health, epidemiology and statistics from
    all over the world because of their manipulation of data. Gotschze
    cherry-picked studies that supported his hypothesis, and disregarded favourable
    studies, based on his misunderstanding of the methodology of cluster
    randomization in screening trials.
    Mammography is not perfect. It doesn’t find
    all cancers, and when women are recalled when we find something on a mammogram
    that needs more tests, there is unavoidable transient anxiety and even
    sometimes a needle biopsy done with freezing to rule out cancer. But women know
    that this is reasonable, and would choose to have the test rather than let a
    patronizing administration decide that they should be spared the anxiety, and
    lose the opportunity to find a small cancer.
    Canadians deserve to hear the truth, not
    Mr. Cassels slagging the Canadian Breast Cancer Foundation. They appear to have
    a better understanding of the science than he does. He should stick to his area
    of expertise.
    Paula Gordon, OBC, MD, FRCPC, FSBI
    Clinical Professor, University of British
    Columbia

  2. Mr. Cassels, a pharmaceutical policy
    researcher, has weighed in on screening mammography. He does women a
    disservice. He quotes only the 25-year update of the Canadian National Breast
    Screening trial, and does not include the fact that this was the ONLY trial of
    mammography screening that didn’t show decreased mortality. It is an outlier,
    and in 2002, the World Health Organization determined that it should be
    disregarded in in future considerations of the benefit of
    mammography. The flaws in the Canadian trial have been documented ad nauseum. But
    every 5 years they publish an update and cause a media frenzy and confusion for
    women.
    When the results of better trials are
    averaged, women invited to have mammography showed reduced death from breast
    cancer of 25-30%. More importantly, in women who actually have mammograms (many
    women invited in trials do not, but are still counted in the mammogram group
    when deaths are counted!) the mortality reduction is in the 40-50% range.
     But Mr. Cassels, whose declared conflict of
    interest is in selling his anti-screening book, says that promoting mammography
    is possibly dangerous. He quotes the harms of overdiagnosis and overtreatment,
    and cites Dr. Peter Gotschze and the Cochrane review, which have been roundly
    criticized by authorities in public health, epidemiology and statistics from
    all over the world because of their manipulation of data. Gotschze
    cherry-picked studies that supported his hypothesis, and disregarded favourable
    studies, based on his misunderstanding of the methodology of cluster
    randomization in screening trials.
    Mammography is not perfect. It doesn’t find
    all cancers, and when women are recalled when we find something on a mammogram
    that needs more tests, there is unavoidable transient anxiety and even
    sometimes a needle biopsy done with freezing to rule out cancer. But women know
    that this is reasonable, and would choose to have the test rather than let a
    patronizing administration decide that they should be spared the anxiety, and
    lose the opportunity to find a small cancer.
    Canadians deserve to hear the truth, not
    Mr. Cassels slagging the Canadian Breast Cancer Foundation. They appear to have
    a better understanding of the science than he does. He should stick to his area
    of expertise.
    Paula Gordon, OBC, MD, FRCPC, FSBI
    Clinical Professor, University of British
    Columbia

  3. Mr.
    Alan Cassels has a bias against early detection to promote his anti-screening
    book; he also admires  Dr. Gøtzsche from Denmark who has a published bias
    against “all forms of screening” (Lancet 1997). Dr. Gøtzsche has
    never had access to individual patient data, he does not know which woman was
    or was not screened, or, even if a breast cancer was diagnosed in a woman who
    did or did not get a mammogram. How can one assess the impact of screening
    then? He and Dr. Welch from the USA offer women statistical manipulation
    weakened by missing facts. Why do these people want to throw women back to the
    Middle Ages when all breast cancers were huge, often ulcerated and most of them
    died from the disease. These gentlemen and Dr. Tony Miller, the leader of the
    flawed “Canadian trials” (trials considered by Prof Paula Gordon from
    Vancouver a “national embarrassment”) never mention the eight properly
    carried out randomized controlled trials that unequivocally proved that early
    detection decreases breast cancer death significantly. I wonder why the
    anti-screening campaign comes from a country with a shameful “study”
    and from Denmark where breast cancer death is the third highest in Europe.
    Something must be wrong with these people; we expect women stand up for their
    cause. We recommend that Mr. Cassels, a pharmaceutical policy researcher
    restricts his activities to his area of expertise.
    Professor
    emeritus Laszlo Tabar, MD, FACR(Hon)

  4. Mr.
    Alan Cassels has a bias against early detection to promote his anti-screening
    book; he also admires  Dr. Gøtzsche from Denmark who has a published bias
    against “all forms of screening” (Lancet 1997). Dr. Gøtzsche has
    never had access to individual patient data, he does not know which woman was
    or was not screened, or, even if a breast cancer was diagnosed in a woman who
    did or did not get a mammogram. How can one assess the impact of screening
    then? He and Dr. Welch from the USA offer women statistical manipulation
    weakened by missing facts. Why do these people want to throw women back to the
    Middle Ages when all breast cancers were huge, often ulcerated and most of them
    died from the disease. These gentlemen and Dr. Tony Miller, the leader of the
    flawed “Canadian trials” (trials considered by Prof Paula Gordon from
    Vancouver a “national embarrassment”) never mention the eight properly
    carried out randomized controlled trials that unequivocally proved that early
    detection decreases breast cancer death significantly. I wonder why the
    anti-screening campaign comes from a country with a shameful “study”
    and from Denmark where breast cancer death is the third highest in Europe.
    Something must be wrong with these people; we expect women stand up for their
    cause. We recommend that Mr. Cassels, a pharmaceutical policy researcher
    restricts his activities to his area of expertise.
    Professor
    emeritus Laszlo Tabar, MD, FACR(Hon)

  5. Tabar has long been accusing anyone who questions mammography with wrong allegations and specious arguments. Example, he claims that “Dr. Gøtzsche has never had access to individual patient data, he does not know which woman was or was not screened, or, even if a breast cancer was diagnosed in a woman who did or did not get a mammogram” and then asks, “How can one assess the impact of screening then?” The same can be asked about his large study where he has refused to share its raw data with independent mammogram investigators for decades and who’s study had been found to be seriously flawed (but he falsely here includes it here among the “properly carried out randomized controlled trials”), like the missing data other had found in his study but he accuses Welch of this. Instead, he plays politics and keeps pointing the finger at the critics of the test. What Tabar never mentions, but everyone should know of, is his massive vested interests in the screening industry, having earned him a fortune. He also goes after the Canadian trials with the same type of hype.
    Gordon uses the same specious arguments as Tabar to “get rid of” critics of mammography: you’re not qualified to speak about it, listen to us were are the experts. What they are primarily is big profiteers of screening or other people who cannot discern the facts not matter of strong the evidence is. Gordon argues as if there is no other sound evidence against mammography besides the Canadian study. Not so, the mammogram industry has simply ignored and obfuscated it. She accuses Gotzsche of manipulating and cherry-picking data when irrefutable evidence shows that is exactly what the entire pro-mammogram view is based on. Gordon and Tabar do women a disservice by spreading propaganda.
    The breast screening industry is one big money-making scheme, presented as if it were proper science and all about women’s well-being, the pink ribbon organizations like the Canadian Breast Cancer Foundationd are fully complicit in it (read through this: http://www.supplements-and-health.com/mammogram.html )

  6. Tabar has long been accusing anyone who questions mammography with wrong allegations and specious arguments. Example, he claims that “Dr. Gøtzsche has never had access to individual patient data, he does not know which woman was or was not screened, or, even if a breast cancer was diagnosed in a woman who did or did not get a mammogram” and then asks, “How can one assess the impact of screening then?” The same can be asked about his large study where he has refused to share its raw data with independent mammogram investigators for decades and who’s study had been found to be seriously flawed (but he falsely here includes it here among the “properly carried out randomized controlled trials”), like the missing data other had found in his study but he accuses Welch of this. Instead, he plays politics and keeps pointing the finger at the critics of the test. What Tabar never mentions, but everyone should know of, is his massive vested interests in the screening industry, having earned him a fortune. He also goes after the Canadian trials with the same type of hype.
    Gordon uses the same specious arguments as Tabar to “get rid of” critics of mammography: you’re not qualified to speak about it, listen to us were are the experts. What they are primarily is big profiteers of screening or other people who cannot discern the facts not matter of strong the evidence is. Gordon argues as if there is no other sound evidence against mammography besides the Canadian study. Not so, the mammogram industry has simply ignored and obfuscated it. She accuses Gotzsche of manipulating and cherry-picking data when irrefutable evidence shows that is exactly what the entire pro-mammogram view is based on. Gordon and Tabar do women a disservice by spreading propaganda.
    The breast screening industry is one big money-making scheme, presented as if it were proper science and all about women’s well-being, the pink ribbon organizations like the Canadian Breast Cancer Foundationd are fully complicit in it (read through this: http://www.supplements-and-health.com/mammogram.html )

  7. Dave89476 does not state his real name or qualifications. And just because he cites a website (the author of the website states that he has no academic qualifications!) does not give him  the credibility of peer-reviewed scientific literature. 

    I hope Dr. Tabar responds to Dave’s slander himself, but will point out that experts in statistics, epidemiology and public health (who cannot be accused of conflict of interest!) from all over the world have criticized Gotzsche for his methodology http://www.ncbi.nlm.nih.gov/pubmed/15075144
    Dave probably doesn’t know that the Canadian National Breast Screening trial was the only randomized trial to show increased mortality from breast cancer, due to flawed allocation (it was not truly randomized), excess contamination because it was the only RCT to invite participate to both control and study groups, and poor quality.

    I clearly have a conflict of
    interest, but it is not financial. Unlike Dave, who presumably has never cared
    for a woman with breast cancer, I earn income by reading mammograms and by
    doing ultrasound exams and needle biopsies when they are necessary. And I do
    so, because based on the science, this is saving lives. I see all patients with
    possible breast cancer: not just the ones who come because a small cancer was
    found at screening, but also those who have found a lump, large enough to feel,
    sometimes with cancer already spread to the lymph nodes in the armpit. State of
    the art reatment is more effective when cancer is detected when it is smaller, and the science
    shows that mortality is reduced when cancer is found earlier.
    Harvard
    researchers reviewed 7,301 women diagnosed with breast cancer at major
    hospitals in Boston from 1990 to 1999 (Cancer, Sept. 9, 2013). 609 women died
    from those cancers. They found that 71% of the women who died from breast
    cancer were among the 20% of women who were not having screening. 

    Screening is not
    perfect; it doesn’t find all cancers, and it finds abnormalities that are not
    cancer. Luckily, most of the others can be ruled out with an extra mammogram
    picture and/or an ultrasound. Only 1-2% of them will need a needle biopsy done
    with freezing, and 20-40% of those will be diagnosed with
    breast cancer.

    So my so-called
    self-interest, is in preventing death from breast cancer.

  8. Dave89476 does not state his real name or qualifications. And just because he cites a website (the author of the website states that he has no academic qualifications!) does not give him  the credibility of peer-reviewed scientific literature. 

    I hope Dr. Tabar responds to Dave’s slander himself, but will point out that experts in statistics, epidemiology and public health (who cannot be accused of conflict of interest!) from all over the world have criticized Gotzsche for his methodology http://www.ncbi.nlm.nih.gov/pubmed/15075144
    Dave probably doesn’t know that the Canadian National Breast Screening trial was the only randomized trial to show increased mortality from breast cancer, due to flawed allocation (it was not truly randomized), excess contamination because it was the only RCT to invite participate to both control and study groups, and poor quality.

    I clearly have a conflict of
    interest, but it is not financial. Unlike Dave, who presumably has never cared
    for a woman with breast cancer, I earn income by reading mammograms and by
    doing ultrasound exams and needle biopsies when they are necessary. And I do
    so, because based on the science, this is saving lives. I see all patients with
    possible breast cancer: not just the ones who come because a small cancer was
    found at screening, but also those who have found a lump, large enough to feel,
    sometimes with cancer already spread to the lymph nodes in the armpit. State of
    the art reatment is more effective when cancer is detected when it is smaller, and the science
    shows that mortality is reduced when cancer is found earlier.
    Harvard
    researchers reviewed 7,301 women diagnosed with breast cancer at major
    hospitals in Boston from 1990 to 1999 (Cancer, Sept. 9, 2013). 609 women died
    from those cancers. They found that 71% of the women who died from breast
    cancer were among the 20% of women who were not having screening. 

    Screening is not
    perfect; it doesn’t find all cancers, and it finds abnormalities that are not
    cancer. Luckily, most of the others can be ruled out with an extra mammogram
    picture and/or an ultrasound. Only 1-2% of them will need a needle biopsy done
    with freezing, and 20-40% of those will be diagnosed with
    breast cancer.

    So my so-called
    self-interest, is in preventing death from breast cancer.

Leave a comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.

Pin It on Pinterest

Share This