The Little Known Truth About Mammograms

Adam Ruins The Hospital – Season 2 | Ep 203, 2017

Mammograms might be able to detect cancer but they can’t tell the difference between different types. Turns out, mammograms can harm and save much fewer lives than you think.

Diagnostic tests : how to minimise harm

We must develop new diagnostic tests to tackle real health problems, not to generate them

New diagnostic tests: more harm than good, BMJ 2017;358:j3314,
06 January 2016.

Defenders against overdiagnosis, BMJ 2017;358:j3487, 20 July 2017.

Although new diagnostics may advance the time of diagnoses in selected patients, they will increase the frequency of false alarms, overdiagnosis, and overtreatment in others.

Bjorn Hofmann, professor of medical ethics at Norwegian University of Science and Technology, explains how to minimise harm. Press Play > to listen to the recording.

Key messages

  • Innovative technologies and ample venture capital are combining to produce new disease biomarkers and mobile monitoring devices
  • These new diagnostics are technologically advanced but do not automatically provide improvements in clinical care and population health
  • They have the potential to help some but also to increase the frequency of false alarms, overdiagnosis, and overtreatment in others
  • Excessive testing and false alarms may increase healthcare workload and shift clinicians’ focus towards the healthy
  • Misleading feedback at both the population and individual levels tends to favour further market growth
  • Clinicians must provide a strong counterbalance: educating patients, respecting baseline risk, thinking downstream, and expecting misleading feedback

Our SoundCloud Playlists

JAMA 2017 Guidance for Modifying the Definition of Diseases

Loose disease definitions cause millions misdiagnoses and excess testing/treatment. Checklist stops disease mongering

A landmark paper addressing overdiagnosis, published yesterday in the journal JAMA Internal Medicine, outlines the first serious attempt to set some global rules for those experts who move diagnostic goalposts that label more people as sick.


No guidelines exist currently for guideline panels and others considering changes to disease definitions. Panels frequently widen disease definitions, increasing the proportion of the population labeled as unwell and potentially causing harm to patients. We set out to develop a checklist of issues, with guidance, for panels to consider prior to modifying a disease definition.


“Medical science is making so much great progress soon none of us will be well”
Allen Frances

We assembled a multidisciplinary, multicontinent working group of 13 members, including members from the Guidelines International Network, Grading of Recommendations Assessment, Development and Evaluation working group, and the World Health Organisation. We used a 5-step process to develop the checklist:

  1. a literature review of issues,
  2. a draft outline document,
  3. a Delphi process of feedback on the list of issues,
  4. a 1-day face-to-face meeting,
  5. and further refinement of the checklist.

The literature review identified 12 potential issues. From these, the group developed an 8-item checklist that consisted of definition changes, number of people affected, trigger, prognostic ability, disease definition precision and accuracy, potential benefits, potential harms, and the balance between potential harms and benefits. The checklist is accompanied by an explanation of each item and the types of evidence to assess each one. We used a panel’s recent consideration of a proposed change in the definition of gestational diabetes mellitus (GDM) to illustrate use of the checklist.

Conclusions and Relevance
We propose that the checklist be piloted and validated by groups developing new guidelines. We anticipate that the use of the checklist will be a first step to guidance and better documentation of definition changes prior to introducing modified disease definitions.

Sources and Media Releases
  • Changes in Disease Definition and Prevalence of a ConditionWiser Healthcare, 04:59 – 16 mai 2017.

    How does a new disease definition impact the prevalence of a condition ?
  • Checklist of Items to Consider When Modifying a Disease DefinitionWiser Healthcare, 03:31 – 16 mai 2017.

    Preventing #overdiagnosis: a checklist to guide modification of #disease definitions
  • Guidance for Modifying the Definition of Diseases, A Checklist, JAMA Internal Medicine Special Communication, doi:10.1001/jamainternmed.2017.1302, May 15, 2017.
  • How to rein in the widening disease definitions that label more healthy people as sick, the conversation, May 15, 2017.

The New War on Cancer

50-Year War on Cancer: Can We Win?

The signing of the National Cancer Act by President Richard M. Nixon on December 23, 1971, was considered a declaration of war on cancer.

In a multi-part series, the National Post explores why we need a new war on cancer.

Cancer nation

Where you live could affect your odds of getting cancer or dying from it.

Interactive map: Cancer is an indiscriminate disease, affecting rich and poor, old and young. Still, Canadians’ odds of getting sick depend surprisingly on where they live.

Why we need a new war on cancer

Over-treating and over-screening is doing patients more harm than good

The issue: Advances in screening and diagnosis are sending some cancer patients down aggressive treatment paths that they shouldn’t be on.
The solution: A new war on cancer and a rethinking of resources.

Drug money

Some cancer treatments cost as much as $33,000 a month, but fall well short of being wonder cures

A Post analysis of 17 cancer drugs that cost between $4,700 and $33,000 a month reveals only three had evidence that they extended lives when approved by Health Canada.

Bankrupt by cancer

Cancer is not just a life-threatening disease ― but a financial disaster.

In Canada, a country that prides itself on looking after the sick, no matter their ability to pay, Canadians are declaring bankruptcy because of cancer.

The fundraising complex

Of the $2.7 billion that cancer charities spent in 2013, only 45 per cent went towards fighting cancer.

The Post’s analysis of cancer funding reveals the depth of inefficiencies in the sector. In 2013, more than half of total funds went to salaries and overhead.

Learning to live with cancer

As science gets better at controlling cancer for longer periods of time, it might be best to kill the battle rhetoric

Nowhere else in medicine is the battle rhetoric more entrenched than in cancer. And its defeating people. Who wants to go war with their own bodies?

Prevention as the ultimate cure

Prevention saves more lives than any cancer drug

However, in the multi-billion-dollar cancer business, efforts to stop people from contracting the illness account for as little as five per cent of what’s spent.

How to reduce your risk of becoming a breast cancer patient by one third

Dr Peter Gøtzsche’s views on breast cancer screening

Video published on 1 April 2015 by John McDougall.

Peter C. Gøtzsche, MD is a Danish medical researcher, and leader of the Nordic Cochrane Center at Rigshospitalet in Copenhagen, Denmark. He has written numerous reviews within the Cochrane collaboration.

Dr.Gøtzsche has been critical of screening for breast cancer using mammography, arguing that it cannot be justified; His critique stems from a meta-analysis he did on mammography screening studies and published as Is screening for breast cancer with mammography justifiable? in The Lancet in 2000. In it he discarded 6 out of 8 studies arguing their randomization was inadequate.

In 2006 a paper by Gøtzsche on mammography screening was electronically published in the European Journal of Cancer ahead of print. The journal later removed the paper completely from the journal website without any formal retraction. The paper was later published in Danish Medical Bulletin with a short note from the editor, and Gøtzsche and his coauthors commented on the unilateral retraction that the authors were not involved in.

In 2012 his book Mammography Screening: Truth, Lies and Controversy was published. In 2013 his book Deadly Medicines and Organized Crime: How Big Pharma has Corrupted Healthcare was published.

The Concern about Overdiagnosis

A clear insight about over diagnosis in less than 3 mns

Video published on 19 Nov 2016 by Show More Spine.

Paul Glasziou’s Interview by Alan Cassels at Preventing Overdiagnosis Conference 2016 in Barcelona, Spain.

Watch more videos about overdiagnosis on YouTube.

Breast cancer screening not associated with a reduction in the incidence of advanced cancer

Mammograms tied to overdiagnosis of breast cancer

The current study offers fresh evidence linking routine screening to over-diagnosis of non-aggressive tumors because it compares outcomes over a single time period in two regions of Denmark – one that offered biennial mammography for women aged 50 to 69 and one that didn’t.

January 2017 Study Abstract

Effective breast cancer screening should detect early-stage cancer and prevent advanced disease.

To assess the association between screening and the size of detected tumors and to estimate overdiagnosis (detection of tumors that would not become clinically relevant).

Cohort study.

Breast Cancer Screening in Denmark: A Cohort Study of Tumor Size and Overdiagnosis, Annals of Internal Medicine, DOI: 10.7326/M16-0270, 10 JANUARY 2017.

Philips Mammography Truck, Brazil via philips_newscenter.

Denmark from 1980 to 2010.

Women aged 35 to 84 years.

Screening programs offering biennial mammography for women aged 50 to 69 years beginning in different regions at different times.

Trends in the incidence of advanced (>20 mm) and nonadvanced (≤20 mm) breast cancer tumors in screened and nonscreened women were measured. Two approaches were used to estimate the amount of overdiagnosis: comparing the incidence of advance and nonadvanced tumors among women aged 50 to 84 years in screening and nonscreening areas; and comparing the incidence for nonadvanced tumors among women aged 35 to 49, 50 to 69, and 70 to 84 years in screening and nonscreening areas.

Screening was not associated with lower incidence of advanced tumors. The incidence of nonadvanced tumors increased in the screening versus prescreening periods (incidence rate ratio, 1.49 [95% CI, 1.43 to 1.54]). The first estimation approach found that 271 invasive breast cancer tumors and 179 ductal carcinoma in situ (DCIS) lesions were overdiagnosed in 2010 (overdiagnosis rate of 24.4% [including DCIS] and 14.7% [excluding DCIS]). The second approach, which accounted for regional differences in women younger than the screening age, found that 711 invasive tumors and 180 cases of DCIS were overdiagnosed in 2010 (overdiagnosis rate of 48.3% [including DCIS] and 38.6% [excluding DCIS]).

Regional differences complicate interpretation.

Breast cancer screening was not associated with a reduction in the incidence of advanced cancer. It is likely that 1 in every 3 invasive tumors and cases of DCIS diagnosed in women offered screening represent overdiagnosis (incidence increase of 48.3%).

Regular Mammograms Risk-Benefit Characterization Theater

Breast-Cancer and Mammography : Consider the Pros and Cons

How Tiny Are Benefits From Many Tests And Pills? Researchers Paint A Picture

Mammograms are said to cut the risk of dying from breast cancer by as much as 20 percent ; some researchers want people to question that kind of thinking.

More Information

Breast-Cancer Tumor Size, Overdiagnosis, and Mammography Screening Effectiveness

NEJM Screening Mammograms, Analysis by Dr. H. Gilbert Welch

Dr. H. Gilbert Welch gives us a brief explanation of the findings of the New England Journal of Medicine article “Breast Cancer Tumor Size, Overdiagnosis, and Mammography Screening Effectiveness“, October 13, 2016.

Study Abstract

The goal of screening mammography is to detect small malignant tumors before they grow large enough to cause symptoms. Effective screening should therefore lead to the detection of a greater number of small tumors, followed by fewer large tumors over time.

We used data from the Surveillance, Epidemiology, and End Results (SEER) program, 1975 through 2012, to calculate the tumor-size distribution and size-specific incidence of breast cancer among women 40 years of age or older. We then calculated the size-specific cancer case fatality rate for two time periods: a baseline period before the implementation of widespread screening mammography (1975 through 1979) and a period encompassing the most recent years for which 10 years of follow-up data were available (2000 through 2002).

After the advent of screening mammography, the proportion of detected breast tumors that were small (invasive tumors measuring

Although the rate of detection of large tumors fell after the introduction of screening mammography, the more favorable size distribution was primarily the result of the additional detection of small tumors. Women were more likely to have breast cancer that was overdiagnosed than to have earlier detection of a tumor that was destined to become large. The reduction in breast cancer mortality after the implementation of screening mammography was predominantly the result of improved systemic therapy.

If screening had been a drug, it would have been withdrawn from the market

Which country will be first to stop mammography screening?

Key points

  • Screening with mammography does not reduce the occurrence of advanced cancers.
  • Rigorous observational studies in Europe have failed to find an effect of mammography screening.
  • Mammography screening produces patients with breast cancer from among healthy women and increases the number of mastectomies performed.
  • The most effective method we have to reduce the occurrence of breast cancer is to stop screening.

Time to stop mammography screening?

The Canadian Task Force on Preventive Health Care should be congratulated for its new recommendations on screening for breast cancer in women at average risk aged 40–74 years. These guidelines are more balanced and more in accordance with the evidence than any previous recommendations.

The recommendations against routine clinical breast examinations, breast self-examinations and magnetic resonance imaging to screen for breast cancer in this age and risk group are all straightforward.

The recommendations on mammography screening are even more conservative than the change in policy suggested by the US Preventive Services Task Force in 2009, which created an uproar in the United States from people interested in maintaining the status quo. The new Canadian guidelines are appropriately cautious, advising against routinely screening women aged 40–49 years. The task force recommends screening women aged 50–69 years every two to three years, although it admits that this is a weak recommendation based on moderate-quality evidence, and screening women aged 70–74 years on the same schedule based on low-quality evidence. The task force also suggests that women who do not place a high value on a small reduction in breast cancer mortality, and who are concerned with false-positive results on mammography and overdiagnosis, may decline screening.

These guidelines are an important step in the right direction, away from the prevailing attitude that a woman who does not undergo screening is irresponsible. Recent research even suggests that it may be most wise to avoid screening altogether, at any age, as outlined below.

The Canadian Task Force on Preventive Health Care decided not to include observational studies in its systematic review unless they were needed to elucidate the harms of screening or the values and preferences of patients. However, important observational studies have been published in recent years, without which a systematic review would be incomplete. These observational studies have been discussed elsewhere and have also been included in an update (currently submitted for publication) of our 2009 Cochrane review of mammography screening.

Doubtful effect of screening

Time to stop mammography screening?; National Institutes of Health PMC3225414 183(17): 1957–1958, Nov 22 2011.

Programming a latest-gen mammography station, nicoyogui.

If screening does not reduce the occurrence of advanced cancers, it does not work. A systematic review of studies from seven countries showed that, on average, the rate of malignant tumours larger than 20 millimetres was not affected by screening. Because the size of a tumour is linearly correlated to the risk of metastasis, this result is evidence against an effect of screening.

Denmark has a unique control group within its population — only 20% of its population was screened during a 17-year period. The annual decrease in breast cancer mortality in the relevant age group (55–74 years) and period was 1% in the areas with screening and 2% in the non-screened areas.Among women who were too young to benefit from screening, the decreases were larger (5% for screened areas, 6% for unscreened areas). Similar results have been reported from the United Kingdom, Sweden and Norway.

A study involving women from 30 European countries showed that the mean decrease in breast cancer mortality between 1989 and 2005 among women less than 50 years of age was 37%; the corresponding decrease was 21% among women aged 50–69 years. The declines began before the start of organized screening programs in many countries and are more likely explained by the introduction of tamoxifen. The introduction of tamoxifen could explain the larger decline seen among young women who often have estrogen-sensitive tumours.

Another study compared three pairs of similar neighbouring countries that had introduced screening 10–15 years apart. The pairs were Northern Ireland and the Republic of Ireland, the Netherlands and Belgium, and Sweden and Norway. There was no relation between start of screening and the reduction in breast cancer mortality.The fall in breast cancer mortality was about the same in all countries. Furthermore, the decline was also about the same as that seen in the United States, where screening started as early as in Sweden.

Screening seems to be ineffective in today’s world for two reasons. First, adjuvant therapy, such as tamoxifen and chemotherapy, is highly effective (even when the cancer has metastasized) but was not often used at the time of the old trials. Second, public awareness of breast cancer has increased, and women tend to see a doctor much earlier today when they have noticed something unusual in their breast. In Denmark, the average size of a tumour decreased by nine millimetres from 1979 to 1989, a reduction that occurred before screening started. In addition, this decrease was larger than the average difference in tumour size seen between screened and control groups in trials (5 mm), despite the tendency for small, overdiagnosed tumours to spuriously exaggerate the difference.

It has often been claimed that mammography screening reduces breast cancer mortality by 30%. However, thorough systematic reviews have estimated only a 15% reduction, and data on tumour size from the trials are compatible with only a 12% effect.This effect is similar to the results seen in the most reliable studies, which showed a 10% effect after 13 years.


Any possible effect of screening on breast cancer mortality must be marginal and could be counteracted by the life-shortening effect that radio-therapy and chemotherapy have when used in healthy women in whom breast cancer has been overdiagnosed (i.e., a diagnosis of breast cancer that would not have been made in the woman’s remaining life had she not undergone screening). The main effect of screening is to produce patients with breast cancer from among healthy women who would have remained free of breast disease for the rest of their lives had they not undergone screening. Compelling data from the US, Norway and Sweden show that most overdiagnosed tumours would have regressed spontaneously without treatment.  In addition, screening substantially increases the number of mastectomies performed, despite routine claims to the contrary by advocates of screening.

The best method we have to reduce the risk of breast cancer is to stop the screening program. This could reduce the risk by one-third in the screened age group, as the level of overdiagnosis in countries with organized screening programs is about 50%.

If screening had been a drug, it would have been withdrawn from the market. Thus, which country will be first to stop mammography screening?

Peter Gøtzsche, MD, 2011.