When mammography detects cancer which is successfully treated, has mammography saved that woman’s life? Probably not

Many years ago (more than I care to remember), I was giving a lecture about health, and more in passing that anything else, mentioned just how ineffective many conventional medical approaches are, including cancer screening. After the lecture I was approached by a woman who took at least some exception to my claim that cancer screening was not very effective. She told me that if it were not for mammography, she would be dead. In short, ‘mammography saved her life’.

When she put it this to me I enquired gently why she felt she could state that with such certainty, and she replied that breast cancer is a killer and that it was only because it was caught early that she did not succumb to it. Besides, her surgeon had told her early detection had saved her life.

I wasn’t intimate with her medical history, but the fact is her firm belief that mammography saved her life is probably just that – a belief. While it’s natural perhaps to imagine that every time mammography picks up cancer that is successfully treated that has saved the sufferers’s life, the fact is this is far from assured.

One reason why mammography may not save lives even when it detects cancer is because breast cancer treatment is actually relatively effective (as cancers go). So, imagine this lady had not had screening and the cancer had been detected clinically (say she or her doctor noticed a breast lump), it is entirely possible that her breast cancer could have been cured despite being detected later. In this case mammography would have not saved her life – it would have just afforded her earlier treatment.

Another very real possibility is that the cancer this woman had would never have bothered her over the natural course of her life anyway – a situation referred to as ‘over-diagnosis’. In which case, again, her life would not have been saved by mammography, but she would have undergone unnecessary treatment which is not without risk, either.

I was very interested to read a recently published paper in which researchers calculated the likelihood that mammography which detects breast cancers that are successfully treated actually saves lives [1].

The researchers made this calculation based on women of different ages, and the different estimates for the ability of mammography to reduce breast cancer death. The very best estimates from old and outdated evidence suggest a reduction in death risk from breast cancer of 25 per cent. However, as the authors point out, never, better evidence suggests that the likely real reduction is risk is between 5 and 10 per cent.

Using a 50-year-old woman as an example, the authors tell us that if mammography reduces risk of breast cancer death by 20 per cent, if mammography detects a cancer which is successfully treated, the chances that this has saved her life are just 13 per cent.

If mammography were to only reduce the risk of breast cancer death by 5 per cent (much more realistic), the chances that mammography had saved this woman’s life are a measly 3 per cent.

In other words, the vast majority of women who have mammography and go on to have successful breast cancer treatment have not had their lives saved at all. This is not a reason not to have mammography. However, it is perhaps worth bearing these facts in mind when we read about or hear of the ‘success stories’ women who have undergone mammography and subsequent successful treatment for cancer. Only a small minority of these women have had their lives saved, despite how it looks and how their stories are often presented.


1. Welch HG, et al. Likelihood that a woman with screen-detected breast cancer had had her “life saved” by that screening. Archives of Internal Medicine. Epub 24th October 2011

10 Responses to When mammography detects cancer which is successfully treated, has mammography saved that woman’s life? Probably not

  1. Valerie H 18 November 2011 at 11:57 pm #

    what about the cancers caused by mammography?

  2. DanC 19 November 2011 at 1:19 am #

    Ridiculous and dangerous premise, Dr B: The point of view that preventive medical procedures are “effective” only if the procedure is shown to save lives.

    This is the pov of the (American) medical-pharmaceutical-insurance complex, that sinister group of people who want you to be sick…the sicker, the better. What’s the use in preventing disease? Less money for their coffers.

    Mammography should be a regularly-scheduled procedure for all women because if cancer is detected and removed, that women can live a better life as long as she lives.

  3. Peter Dingle 19 November 2011 at 1:27 am #

    Unfortunately DanC has it around the wrong way. Mammography is not preventative medicine it is early detection and is a part of the huge cost blow out that DanC talks about. We continue to divert scarce money to treatment, including early detection, over treat cancers that would never have caused a problem with treatments that in themselves are deadly.
    The answer is not treatment, including early detection it is prevention. Breast cancer rates continue to increase. it is not genetic but epigenetic. It is our diets and lifestyle. We see this when people migrate from low cancer countries to western nations, within a generation they take on the diseases of the host nation.
    If we are serious bout reducing the cancer incidence (and survival) perhaps we need to think about what we eat and what we do.

  4. Peter Dingle 19 November 2011 at 1:31 am #

    John. I also forgot to mention that I love your articles. As a health researcher of 25 years, retired university professor, you are so spot on and so consistent with all of my own findings.
    thank you

  5. anna@nibootcamp 19 November 2011 at 12:02 pm #

    The thing that worries me most about Breast Cancer is, women get it, have it removed and continue their lives as they always have. The tumour is a warning to women to say you need to make changes to your lifestyle like reducing processed foods and alcohol and increasing exercise. It’s pointless to go through the treatment nightmare and stay the same!

  6. DanC 20 November 2011 at 9:43 pm #

    Ah, Prof Dingle. In between hugely expensive and unnecessary MRI scans you can counsel patients to cut back on the saturated fat and get more exercise.

    Please re-read Dr Briffa’s blog. He’s coming from the premise that early detection of cancer does NOT save lives therefore it should not be done. No women should ever go into a mammography thinking it will save or extend her life.

    Anna: I would never advocate submission to a treatment that would not make you better. The requirement of early detection is that there exists a treatment that will help you. Dr Briffa seems to agree that surgery to remove a small, early-stage tumor is beneficial.

  7. John Briffa 21 November 2011 at 12:17 pm #


    Where did I state in the blog that mammography does not save lives? Where did I state that mammography should not be done?

    It’s not Peter Dingle who needs to re-read this blog post, DanC, it’s you.

  8. Elizabeth 3 January 2012 at 3:36 pm #

    Thanks for an informative article.
    It will be interesting to see what comes out of the review of breast screening going on in the UK. I’ve been watching this area closely for a few years now and have declined mammograms, an informed decision.
    I find it incredible that Breast Screen in Australia don’t even mention over-diagnosis to women and I feel they inflate the benefits of screening. They also “cherry-pick” research only presenting research that favours screening. It is all about protecting the program, not women. We have no advocates here keeping these programs honest, so IMO, both cervical and breast screening has always operated outside the law (no informed consent) and proper ethical standards. Attitudes and conduct are very different in prostate screening.
    Helen Zorbas from Breast Screen was on television a month or so ago informing women of a Swedish study that showed 30% less mortality over the long term for screened women – she felt this should reassure women – the program here is under pressure to reach a 70% target of women aged 50 to 69 and failed once again last year. I have no problem with Ms Zorbas mentioning that study, but she omitted to mention a later study that suggests the fall in the death rate is about better treatments, not screening. It’s that sort of deception that concerns me….you mention both studies, if you’re being fair to women. The other shameful thing: not one doctor stepped forward to warn women of this critical omission, not one – all silent.

    At this stage I don’t trust anything coming from these authorities, I assume it’s misleading and I’m usually right. Our programs seem to serve political and vested interests and IMO, women are treated with near contempt. Fortunately, there is real information available in the UK and elsewhere and that enabled me to make an informed decision. The summary put together by the Nordic Cochrane Institute was a great help. “The risks and benefits of mammograms” is at their website, most women here will never see it.
    I think these screening programs need a major shake-up…attitudes and conduct need to change, they are not in a privileged position which gives them the right to do as they please.

  9. BG9150 14 January 2012 at 6:01 pm #

    I need some nutritional advice to help me with my breast cancer and my emotional response to it. I am post mastectomy, pre reconstruction, and taking Arimidex – for another 5 years at least. A low oncotype DX score has meant I avoided chemotherapy and complete removal of the affected breast tissue has meant no radiotherapy either. Sentinal node negative and no reason to believe I have mets. First diagnosed at the end of May 2011.
    It came as a big shock of course. I have a 7 year old son, am married (not happily), am in my 3rd year at University (Geology & Biology BSc) and I work part-time helping people in debt. I am now a raging alcoholic which I know doesn’t help but the anaesthetic effects are compelling. My temper is short, I sleep badly and am sometimes unable to muster the impetus to do anything other than sit on the sofa all day; my studies are suffering badly and the faculty has agreed that I spread this year over two.
    I have always had an interest in good food, have never had a taste for junk/convenience food and am at my wits end – I have to get a grip on my life and don’t now where to start.
    I have just bought your new book and have read most of it.
    Thans for reading

  10. sheila 28 February 2012 at 7:33 pm #

    Dear Becky. Have you come across Professor Jane Plant’s book ‘Your Life in Your Hands’? It provides a lot of scientifically researched information on some of the causes of cancer, dairy products feature predominately.

    Hope this helps

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