Does not apply to high risk patients. If you have already had breast cancer or you have a close family history of breast or ovarian cancer, this information does not apply to you and you may well benefit from regular screening tests.
Breast Cancer Screening
Surely all doctors want to prevent breast cancer deaths? Yes!
Would I have a mammogram if I were a woman? No way!
There are about 28 hundred new cases of breast cancer each year in Ireland, mostly in women. There are about 650 deaths. [ Cancer Trends, National Cancer Registry, 2016]
Breast screening in Ireland, as elsewhere, is undertaken using X-rays of the breast called mammography. These are really good at spotting potentially fatal cancers. And that's precisely the problem- mostly the cancers are of low potential for causing death and don't need to be diagnosed at all and we cannot really tell which ones are which.
No, seriously! (You might have thought we would have worked that out before we started advertising on TV that all women should be screened.)
Trouble is, mammograms spot loads of cancers that that are indolent. By this I mean, that by having a mammogram you stand a really high chance of spotting a slightly suspicious piece of breast that may have mild cancer but which would never have developed into the sort of breast lump that we all know and fear. So what?
Well, look at the picture. This is a pretty neat result of a mastectomy of the right breast. The tube is a temporary drain to evacuate blood and fluids that would complicate the healing. This lady will likely have months of chemotherapy and /or radiation therapy to mop-up any missed cancer cells. She will have years of anxiety and you can be very sure she won't be getting life insurance for the loan she had meant to take out.
Isn't she alive ? And hasn't she a great chance of surviving!? Wasn't she lucky she had that mammogram and the cancer was really early?!
The answer to these questions is Yes, Yes and No.
Yes , she's alive, (as long she doesn't have an incredibly rare mishap during her surgery or recovery, or as a result of having her immune system whacked by her chemo and radiotherapy.)
And Yes, she will very likely survive, as the death risk from breast cancer isn't as bad as people think. In fact, when you start operating on people with indolent cancers, who wouldn't have died even if you hadn't treated their cancer at all, death rates among people treated start to look really good.
But No! You couldn't say she's lucky because there's a much better than even chance that she didn't need any treatment in the first place. She didn't need to have major surgery, endure chemotherapy and/or radiation therapy and she could have gotten on with her life as before.
How can that be? By most estimates, the burden of over diagnosis in breast cancer screening amounts to about three cases of false cancer for every one case that would have been fatal.[Houssami N. Overdiagnosis of breast cancer in population screening: Does it make breast screening worthless?Cancer Biol Med 2017.]
So , next time you hear someone say 'Mary was lucky, they caught it early!' you should think (to yourself, of course) 'Poor Mary, more than likely, she didn't need to go through all of that.'
Next time you see the cosy advert for Breastcheck on TV, with the girls urging each other to go and get checked '..sure it only takes a few minutes..' spare a thought for the three out of four girls who spend a lifetime with a diagnosis of breast cancer they shouldn't need to have suffered.
Well, that's a very negative position to take, you might counter. And yes, it is pretty hopeless, to say that we cannot figure out which of those abnormal mammograms ought to be treated and which ought to be left alone.
Doctors still try to operate on the basis of 'Do No Harm' It could be argued that mammography does much more harm to individuals with indolent cancers than good.
Screening for breast cancer also does harm to those who have real breast cancer, by diverting resources away from finding and providing cures to our population. At a 2018 conference ' Gathering around Cancer' Prof M Keane, a leading oncologist from Galway openly questioned why we keep spending money on such a bad screening tool. Until we have a better method for figuring out which cancers are which, we ought to consider spending our limited funds on improving the cure of real cancers.
Maybe something better will come along, but until then for women without high risk of breast cancer for other reasons, I would advise checking out of Breastcheck.
Effectiveness of and overdiagnosis from mammography screening in the Netherlands: population based study
BMJ 2017; 359 doi: (Published 05 December 2017)
Conclusions The Dutch mammography screening programme seems to have little impact on the burden of advanced breast cancers, which suggests a marginal effect on breast cancer mortality. About half of screen detected breast cancers would represent overdiagnosis.