Does mammography save lives? Not according to the latest study.

The common perception of mammography is that, by detecting breast cancer earlier than it would otherwise be, it saves women’s lives. However, there is quite some evidence to suggest that many women need to be screen for one life to be saved, and on top of this we have adverse effects such as over-diagnosis (the detection and treatment of breast cancers that would never have bothered a women during the natural course of her life if left undetected).

A new study casts fresh doubt on the effectiveness of mammography as a ‘life-saver’. It involved long-term follow-up of a group of about 90,000 women in Canada, half of whom had been selected for mammography (five mammograms over five years) or no mammography (but did receive at least one breast examination).

During the entire 25-year study, 3,250 women in the mammography group and 3,133 in the non-mammography group were diagnosed with breast cancer. Basically, in this setting, mammography did not improve breast cancer detection. But more importantly, deaths from breast cancer were virtually identical across the two groups. In other words, screening about 45,000 women for 5 years did not reduce their risk of breast cancer compared to breast examination.

This study also assessed over-diagnosis. According to the data, for every 424 women screened, one woman had a breast cancer detected that would not have bothered her if left undetected and untreated.

All-in-all not a great advert for mammography, and another piece of evidence that demonstrates that this practice has been vigorously promoted by some even though the evidence for it is not strong at all.


1. Miller AB, et al. Twenty five year follow-up for breast cancer incidence and mortality of the Canadian National Breast Screening Study: randomised screening trial. BMJ 2014; 348:g366

16 Responses to Does mammography save lives? Not according to the latest study.

  1. Vanessa Schaffeler 14 February 2014 at 7:10 pm #

    ….not to mention the fact that bombarding living tissue with ionising radiation can contribute to cancer in any case……(I used to be a radiographer so was taught about cumulative effects of x-radiation)

    • Esther Lemmens 14 February 2014 at 9:52 pm #

      That’s my belief too Vanessa, good to see it confirmed by someone who knows the ins and outs. Hence, I’m not taking part!

  2. Liz Smith 14 February 2014 at 9:18 pm #

    Many moons ago, it could be 20 years, Danish scientists said this about mammograms and so my friends and I stopped having the horrendous procedure that felt like slamming your breast in the fridge door. Coupled with the radiographers attitude – usually went something like – ‘good job you have large breasts, think about those with small ones.’

    My sister in Australia was lucky enough to have scans which were according to her were gentle and certainly not painful. We read that mammograms could damage tissue in the breast and they had operative procedure that was unnecessary, and as you said would not have troubled them,

    Hope more women read this article – it may make them ask their doctor what is the effect of having mammograms and write down their answer, I find doctors answers are carefully worded when you write them down, as they know you can read and re-read their words.

  3. Sylvia 15 February 2014 at 7:38 am #

    I always did wonder why there was so much interest in breasts as opposed to, say, prostrates…

  4. greensleeves 15 February 2014 at 10:23 am #

    Never had one, after reading a study 15 years ago that showed how common false positives were, something like 45%. Repeating the test actually increased the false positive rate!

    Probably 35% of women treated for “breast cancer” in the US never had it, period. It’s shocking how poor this test is.

  5. wiseuptohealth 15 February 2014 at 6:31 pm #

    This is why I had thermographic imaging instead, and then made sure I wrote to my GP to inform her not to pester me anymore for mammograms, and to let her know why I reject them in favour of thermographic imaging. I sent a copy of my results and asked for them to be kept with my medical records.

  6. Tony Kerstein 15 February 2014 at 7:44 pm #

    My 74 year old wife found what she thought was a pimple but turned out to be a tumor which needed a lumpectomy followed by radio-therapy, which we are in the middle of now. The point being that neither the mammogram nor the scan detected it, but only the biopsy. Thank God the doctors didn’t rely on the first two.

  7. Liz 18 February 2014 at 11:24 am #

    I had a routine mammogram last year and was found to have a deep stage 3 invasive cancer. No lumps or bumps. Had surgery followed by radiotherapy. This would have not been detected without the mammogram. Your comments please
    Thank you

  8. Dr John Briffa 20 February 2014 at 4:44 pm #


    Do you believe that mammography saved your life?

  9. Liz 21 February 2014 at 12:05 pm #

    Without the mammogram I would have been completely unaware of the invasive ductal cancer (invasive stage 3) so I not saying it saved my life at present but could have a future impact and hopefully removed before it became too late and more aggressive treatment was necessary.

  10. William L. Wilson, M.D. 24 February 2014 at 2:38 pm #

    Dr. Peter Gotzsche showed this to be true over 10 years ago:

    It’s sad that despite this evidence, little has changed. Many people have their mind made up about the benefits of mammography, so it’s an uphill battle to change their perspective.

    • Imero 26 February 2014 at 1:47 am #

      This is true. But even many years prior to that there were convincing voices and good evidence dissuading the mammogram industry to go forward with the systematic use of screening (see The Mammogram Myth by Rolf Hefti). It’s difficult to change someone with a closed mind…

  11. Liz 7 March 2014 at 9:04 am #

    I turned 50 last autumn and have now been called for ‘routine breast screening’ here in Malta. Which all sounds so efficient. In fact, visiting the gynaecologist last week (after years of not), she advised me in strong terms to book a mammogram. I’ve always been sceptical and am set on not going. But let’s face it, the mantra is so strong to ‘go’ or ‘else’ that it’s hard for a woman to resist (esp if the service is free and billed as for our own good). We are considered poor uninformed and stupid not to take the service up. I am perfectly fine, no lumps or bumps so should I or should I not go? Or should I opt for a private ultrasound instead? I like the idea of taking health into my own hands, not be dictated to.

    • Dr John Briffa 7 March 2014 at 9:17 am #


      This is perhaps one example of where a patient may be in a position to inform and even ‘educate’ a doctor.

      As information gets more widely available and disseminated (principally via the internet), we doctors are going to have to get used to the idea that sometimes we don’t know best, but our patients do.

  12. Suzanne 13 March 2014 at 7:15 pm #

    I for one am grateful for my mammogram. I have large breasts that are quite difficult to selfexamine and my tumour was discovered very early. Now “all” I have to suffer through are 3-5 weeks of radiation and 5 years of “antihormones”. Not much fun, but preferable to chemo, losing my breast, radiation and antihormones and an economy shot to pieces.

  13. Zoe Sayer 20 March 2014 at 9:34 am #

    What about the 117 women who had a mammogram and were diagnosed who wouldn’t otherwise have been? How were the non-mammogrammed women diagnosed? As a younger woman with breast cancer, if I’d been ultrasounded/mammogrammed when I initially found my lump instead of 2 1/2 years later I could have caught it before it spread to my lymph nodes and potentially have avoided chemotherapy. I presume you’ve not been treated for cancer? In my opinion ANYTHING that helps people avoid what I have gone through is worthwhile. And I’m sure the 117 families are glad their mothers/sisters/wives/daughters didn’t die a horrible death from invasive cancer.

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