Mammography Screening

Truth, Lies and Controversy

Peter C Gøtzsche (sic)


Reviewed by Mira de Vries

Scientific research indicates that by screening for breast cancer with mammography, it can be detected and thus treated in an early stage enabling the affected women to live longer.
The above statement sounds so logical, who would think to question it? The answer is Peter Gøtzsche.

There are two types of research trials, observational and randomized. Gøtzsche dismisses the first kind as unhelpful. Randomized trials entail following two similar but separate groups of people, for instance women of a certain age who are screened, and women of the same age who are not. The screened women are called the study group, the unscreened women are called the control group. After a certain period, say ten years, the trialists (his word, used frequently) will compare the length of survival of cancer patients in the study group to those in the control group. But even when no outright fraud or manipulation of statistics is involved, the outcome is deceiving, says Gøtzsche. For instance:
  • Much of what passes as scientific research is methodologically faulty, for example by comparing unlike groups;
  • Some research is set up so complicatedly that it is impossible to draw any valid conclusions;
  • The conclusions drawn from research frequently reflect wishful thinking rather than actual findings;
  • Unwelcome research outcomes are often censured;
  • Early detection of cancer lengthens the interval between diagnosis and death, which in itself does not mean that the affected person would have lived less long if the cancer had been detected later;
  • Diagnostic tests are grossly inaccurate – they are subjective judgments and particularly small or inactive tumors are likely to be judged differently by different pathologists or radiologists;
  • When a slow-growing tumor is treated, survival is good, not because the tumor was treated early, but because it was never going to be life-threatening anyway;
  • What statistics actually reveal is that women in the study groups are a quarter more likely to be diagnosed with breast cancer than women in the control groups, and as a result be “treated” by disfiguring amputation, radiotherapy, and chemotherapy;
  • Although women in the study groups are less likely to die from breast cancer than those in the control groups, they are more likely to die from other causes such as heart disease, suggesting that many of the tumors treated were benign but the treatment was not;
  • Screening is unlikely to catch precisely the dangerous, fast-growing tumors that kill because they appear and develop suddenly, not at the time of screening;
  • Cause of death is often recorded sloppily and/or biased, skewing the outcome of research.
The best time to diagnose cancer, Gøtzsche opines, is when symptoms appear, not before. Screening will only lead to unnecessary alarm, over-diagnosis, over-treatment, and an unjustified sense of safety when nothing is found. This viewpoint is unpopular with professionals who stand to benefit economically or politically from screening programs.

Gøtzsche only fleetingly addresses some of the objections to mammography that I have heard from women who have experienced it. Firstly it requires mechanical pressure on the breast which is painful. Gøtzsche, like the screening advocates, dismisses the pain as temporary, as though pain were not an indication of injury. Secondly mammography entails radiation which in itself is carcinogenic. He doesn’t mention at all that the experience is degrading.

An issue to which he does draw due attention is the intimidating tone of the invitations. Women are told that if they wish to not participate, they must inform the screening agency of their reasons, preferably on their website, within a certain -- short -- period of time. I personally am a woman living in one of the countries Gøtzsche mentions for having implemented screening programs, the Netherlands. I always ignore the invitations and never follow the opt-out procedure. There is no penalty except that I receive several vexing follow-up letters. One even threatened that if I did not respond, someone would come to my door to ask me why. Fortunately, no one did, or the person came when I wasn’t home. Yet the language of the invitation gives one cause to wonder whether screening will always remain optional.

The invitations are also dishonest, not only as Gøtzsche explains by misrepresenting the advantages and disadvantages of screening, but also for instance by trying to gain my confidence by listing my family physician as sender although he has nothing to do with the project.

Gøtzsche does not mention at all another of my objections. For the invitations to be sent the government waives privacy laws and passes personal information about me without my permission on to the party commissioned to do the screening. If I were to follow the opt-out procedure online, it would have my IP-address too.

However, most of this book is not really about screening, mammography, or breast cancer. It is about human relationships and emotions, namely among professionals involved in medical science including physicians, researchers, manufacturers, journalists, directors of patient advocacy societies, and politicians. Whoever imagines them as stringently honest and transparent, standing selflessly shoulder to shoulder to benefit mankind, has rather the wrong picture in mind.

Often authors annoy me by riddling their book with inconsistencies that muddle their message. Gøtzsche does not in this book except for one slip. Towards the end, while criticizing health care in the United States, Gøtzsche writes, “Healthcare should not be regulated by market forces.” Then by what should it be regulated, government forces? He has just written an entire book detailing how government wastes public funds and human lives by making wrong health care decisions. On the very next page he calls a publication by the British National Health Service “an amazing example of political spin.” A paragraph further he laments that “the [British] Department of Health will not allow NICE [National Institute for Health and Care Excellence] to touch the holy cow.” A few chapters earlier he reported that the Danish Council of Ethics poses that the screening program should be evaluated by lay people. What does Gøtzsche think “market forces” are? Market forces are operational only in a free market. That means that individual citizens are allowed to make their own choices, without interference by the government funds and propaganda that Gøtzsche berates throughout his book. In a free market, individual citizens do not always make health care choices that are rational and frugal, but at least they aren’t bullied by the state to make bad decisions. By the way, there has not been a free medical market in the US since 1891.

In the last paragraph before the appendixes Gøtzsche states that screening for breast cancer “may be the biggest ethical scandal ever in health care.” However, his next two books in English indicate that he may have since changed his mind.

Chapter 24 contains some brief explanations about (breast) cancer which would be handy to know from the beginning of the book, so I recommend reading Chapter 24 first.

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