Another Fine Mess

 

Did you guess from the title that this short piece is about the seeming inability of the British Government to run well, most things but especially IT programmes? Of course you did! Provoked by the latest National Health Service furore. In case you’ve been away with the fairies for a bit, a major cock-up in its computer system has just come to light whereby, between 2009 and 2018, it failed to invite 450,000 women between the ages of 68 and 71 for breast screening. Secretary of State for Health, Jeremy Hunt (our man usually on hand with a can of gasoline when there’s a fire), told Parliament that “there may be between 135 and 270 women who had their lives shortened”. Cue: uproar, headlines: HUNDREDS of British women have died of breast cancer (Daily Express), etc.

Logo credit: Breast Cancer Action

I’ve been reluctant to join in because I’ve said all I think is worth saying about breast cancer screening in two earlier pieces (Risk Assessment and Behind the Screen). Reading them again I thought they were a reasonable summary and I don’t think there’s anything new to add. However, this is  a cancer blog and it’s a story that’s made big headlines so I feel honour-bound to offer a brief comment — in addition to sympathizing with the women and families who have been caused much distress.

My reaction was that Hunt was misguided in mentioning specific numbers — not only because he was asking for trouble from the press but mainly because the evidence that screening itself saves lives is highly questionable. For an expert view on this my Cambridge colleague David Spiegelhalter, who is Professor for the Public Understanding of Risk, has analysed the facts behind breast screening with characteristic clarity in the New Scientist.

Anything to add?

I was relieved on re-reading Risk Assessment to see that I’d given considerable coverage to the report that had just come out (2014) from The Swiss Medical Board.  They’d reviewed the history of mammography screening, concluded that systematic screening might prevent about one breast cancer death for every 1000 women screened, noted that there was no evidence that overall mortality was affected and pointed out that false positive test results presented the risk of overdiagnosis.

In the USA, for example, over a 10-year course of annual screening beginning at 50 years of age, one breast-cancer death would have been prevented whilst between 490 and 670 women would have had a false positive mammogram calling for a repeat examination, 70 to 100 an unnecessary biopsy and between 3 and 14 would have been diagnosed with a cancer that would never have become a problem.

Needless to say, this landed the Swiss Big Cheeses in very hot water because there’s an awful lot of vested interests in screening and it’s sort of instinctive that it must be a good thing. But what’s great about science is that you can do experiments — here actually analysing the results of screening programmes — and quite often the results turn to be completely unexpected, as it did in this case where the bottom line was that mammography does more harm than good.

This has led to the recommendation that the current programmes in Switzerland should be phased out and not replaced.

So we’re all agreed then?

Of course not. In England the NHS recommendation remains that women aged 50 to 70 are offered mammography every three years — which is just as well or we’d have Hunt explaining the recent debacle as new initiative. The American Cancer Society “strongly” recommends regular screening mammography starting at age 45 and the National Cancer Institute refers to “experts” that recommend mammography every year starting at age 25 for women with mutations in their BRCA1 or BRCA2 genes.

The latter is really incredible because a study published in the British Medical Journal in 2012 found that these mutations made the carriers much more vulnerable to radiation-induced cancer. Specifically, women with BRCA 1/2 mutations who were exposed to diagnostic radiation (i.e. mammography) before the age of 30 were twice as likely to develop breast cancer, compared to those with normal BRCA genes.

They are susceptible to radiation that would not normally be considered dangerous because the two BRCA genes encode proteins involved in the repair of damaged DNA — and if that is defective you have a recipe for cancer.

Extraordinary.

So it’s probably true that the only undisputed fact is that we need much better ways for detecting cancers at an early stage of development. The best hope at the moment seems to be the liquid biopsy approach we described in Seeing the Invisible: A Cancer Early Warning System? but that’s still a long way from solving a general cancer problem, well illustrated by breast mammography.

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Behind the Screen

Anyone who’s romped through to the closing pages of Betrayed by Nature will (we hope) be grateful to have come upon a succinct summary of the pros and cons of screening, particularly for breast cancer. In the UK screening (i.e. mammography: see Breast Cancer – Seeing Red, Jan 2012 for explanation) is offered to women aged 50-70 every three years – so clearly ‘we’ think it’s a Good Thing. However, the waters are less than crystal clear because several studies have concluded that as many as one in three cancers identified by mammography would not cause any symptoms during the lifetime of the patient  – and suggested that countries should spend the money on other things. The simple message you were relieved to read in BbN was that, whilst the matter is controversial, if you are offered screening, accept – whilst being aware that a ‘positive’ is not always a signal for intervention (by surgery and drugs) and that in deciding on a course of action you should be guided by the best advice your clinicians can give.

Photo: Alamy

Trying to bring resolution to this complicated and important matter, yet another ‘official review’ has just appeared in The Lancet – predictably accompanied by some absurdly inflammatory press headlines. So, ignoring them and your groans – and because it is important – can we recap the key points and reassess the clear BbN message? Of course we can – that’s what we do in “Cancer for All.”

Any type of screen for signs of cancer has two problems for those on the receiving end. First it will miss some and second it will sometimes pick up things that, although abnormal, will never become life-threatening. This latest report estimates that screening reduces the relative risk by 20%, i.e. prevents one breast cancer death for every 235 women invited for screening, equivalent to 43 preventions per 10,000 women aged 50 who are screened over the next 20 years. The downside is that about 130 women in every 10,000 are what is called ‘overdiagnosed’: they receive treatment for something that could simply be left alone. Of course that’s highly undesirable as well as stressful and unpleasant for the patient. However, it is rarely fatal – and at least carries an element of reassurance that they won’t develop breast cancer.

So, in the light of the newest info, is BbN’s take in need of modification? No, it’s just fine. What a relief!! But just bear a couple of other points in mind: the sensitivity of screening is gradually improving and dramatic improvements in analysing tumours at the molecular level mean that ‘overdiagnosing’ will decline. As we’ve pointed out, the system isn’t perfect – then neither are we or we wouldn’t get cancers – but it’s heading in the right direction.

References

Independent UK Panel on Breast Cancer Screening. The benefits and harms of breast cancer screening: an independent review. The Lancet October 2012.

http://www.telegraph.co.uk/health/healthnews/9641609/Breast-cancer-screening-harming-thousands.html