Many governments and health agencies like to push mammography, despite the fact that it does not work so well. Not only does it benefit only a tiny fraction of women who undergo mammography, it can harm women too. One way it can do this is by picking up cancers that would not have bothered women over the courses of their lives if left alone. This, of course, exposes women to unnecessary treatment and often much anxiety.
Another potential consequence of mammography is that it can pick up ‘false positives’. Basically, suspicious lesions that turn out not to be cancer at all. One might argue that it’s better to be safe than sorry. But, even though I’m not a woman I’m reluctant to use this argument to negate the stress and anxiety of being recalled after a mammogram on the basis that something (not sure what) has been found and further investigations are required.
This week saw the publication of a study which sought to ascertain just how common false positives are as a result of regular mammography screening [1].
In the UK, current guidelines are for women to attend for a mammogram every three years from about the time they are 50 until their mid-70s. In the US, official guidelines are for mammograms to be done every two years. However, some ‘experts’ believe more frequent, annual, screens are better. While the official recommendation is for mammography to start at 50 in the US, some believe it should be commenced aged 40.
In this study, researchers calculated the percentage of American women who had a false positive test over a 10-year period.
- With screening every two years, 41.6 per cent of women had a false positive examination.
- With annual screening, this percentage was 61.3.
- About 8 per cent of women screen annually will go on to have an unnecessary biopsy too.
In addition to the anxiety such testing will usually induce, there is also the risk of scarring. And let’s not forget the cost.
I’m not against mammography. What bothers me is that women invited to attend for it are often not given the full facts. In general, the purported benefits are stressed, and the potential downsides not made plain to women. Earlier this year I wrote about a publication in which breast screening researchers accused scientists here in the UK of misleading women over the benefits and harms of mammography. In particular, there is a belief that pro-mammography scientists continue to cling to outdated concepts that more contemporary science proves to be incorrect. See here for more on this.
Whether a woman attends for mammography is a personal choice in the end. In my view it’s simply unethical to keep the best information we have from women for reasons that perhaps have to do with money and politics. Without the full facts, how are women to make an informed choice? It’s interesting to note that about half of American women just don’t have their mammograms as advised. As I speculated here, perhaps some of these women have educated themselves and learned stuff their government is not transparent about, and just decided mammography is not for them.
References:
1. Hubbard RA, et al. Cumulative probability of false-positive recall or biopsy recommendation after 10 years of screening mammography: a cohort study. Ann Intern Med. 2011;155(8):481-92
Relation between breast cancer mortality and screening effectiveness: systematic review of the mammography trials
says
Given that the size of the bias was similar to the estimated screening effect, screening appeared ineffective
and
Natural history of breast cancers detected in the Swedish mammography screening programme
says
many invasive breast cancers detected by repeated mammography screening do not persist to be detected by screening at the end of 6 years
I think we would be better off if we spend more time and money PREVENTING cancer incidence by improving Vitamin D3 and Melatonin levels and we should be able to increase the percentage of those early potential cancers disappearing rather than growing. There are promising papers available if we search pubmed for Green tea breast cancer Curcumin breast cancer resveratrol breast cancer and these are often potential interventions that work better combined that individually.
I have read a lot previously about the downsides of mammography, read the Cochrane report and listened to Michael Baum’s talk at UCL (available here: http://www.youtube.com/watch?v=JxDnRMU-l7w), so when I was given an appointment recently I didn’t go. What annoyed me was that I was not asked if I wanted a mammogram, an appointment was automatically made for me. Some women may feel obliged to have the test because of this.
I AM against mammography – it’s irradiation by any other name, which is itself carcinogenic. It may be slight compared to CT scans but there is a metanalysis that seems to suggest an increased risk. Why is there no use of thermography?
An American pen pal said recently that a vast advertising effort was being made for them to have mammograms. When some journalist investigated what the pressure was it came out that the people pushing the mammograms were the company who manufactured the xray machines. My sister in Oz used to have thermography or scan. Danish research was saying this about mammograms must be at least 15 years ago.
This seems to be the same for – pushing fluoride – gardisil – and guess what – flu jabs. Hopefully Americans will come to their senses and stop all this heavy sell, seems what they do this year we may do next year.
Might be useful to measure oestrogen analytes to check they’re being metabolised. As some of the most aggressive cancers are oestrogen secreting this is a very useful test. It’s non invasive just a bit time consuming as it involves a 24 hour urine collection but well worth it.
Some years ago I met a neighbour who told me she was having chemo-therapy for breast cancer. I asked if she had had mammograms and she said “Yes, six weeks before the lump was exrayed -it hadn’t showed up on my mammogram.”
Prevention is better than cure – maybe/a> Plain speaking on the topic from Dr Malcolm Kendrick.