Margaret McCartney's Blog, page 10

What does “for earlier detection” mean?

It’s used here, on Breastlight’s home page. If you search for them on Google, it comes up; “Breastlight TM; breast exam, breast checking, breast screening..”

I’d like to know what kinds of things come to mind when we are told this device is for ‘earlier detection’.

 

 

( I know what I think, but I’d like to know what others think.)

 

The Advertising Standards Authority – fit for purpose?

I’ve just had a complaint responded to. The company concerned will now apparently withdraw their non evidenced based claim that their product “helps detect cancer early”.

This claim has been made for some time, it’s nonsense, and it’s right that it goes.

But: the letter from the ASA says that since the company will voluntarily amend their website, they will take no further action, it will be noted on their website  as an ‘informally resolved case’ (which means no details of their potentially dangerous previous advert and reason for it’s withdrawal) only, and I have to ‘treat the contents of this letter as confidential’, which presumably means that I’m not allowed to say which company offering supposedly early detection cancer devices (they aren’t) have amended their advertising.

So what will happen if I name the company and what they’ve said and what they’ve changed? Is this a system that is fit for purpose?

 

 

DCIS, overtreatment and professionalism

There’s an article in the Guardian describing the US treatment of a woman who had DCIS diagnosed at screening, in one breast.

She went on to have bilateral mastectomy, with flap reconstruction, an autologous blood transfusion, and a stay in ITU. The author writes

” It is so confusing. What was that all about? Cancer? Really? But it was so tiny. Why was the operation so huge? Why has my body been what my plastic surgeon likes to call “completely remodeled”, at a cost of $250,000 to my insurance company, just because of what my radiologist described as “a handful of atypical cells”?”

and

“My goal all along has been to put this experience behind me as fast as possible before carrying on with life as normal. The cost is insane, the trauma has been considerable. I wish both had been less. But given my options, I am comfortable with my choice.I wish there had been another option, though. I wish there was a way of eliminating these cells without taking out so much of my body. I wonder how long it’ll be till that option exists?”

These are good questions, but are not addressed in the article. There’s a massive problem in terms of what ‘normal’ is (the article is entitled “My 40 day breast cancer” and I think we can be safe to assume that the DCIS was not present for only 40 days.) Most of us will have something not ‘normal’ if we are put into a scanner – the very real problem medicine now faces is working out which is likely to be damaging and which should be ignored.

What do we know about DCIS? We know that ever since we started screening for it, rates of diagnosis have increased. We know that many surgeons have been very concerned about overtreatment – there has been a large movement away from mastectomy since trials showed that lumpectomy and radiation therapy was as good for localised DCIS . We should also remember that survival after DCIS is close to 100%. It’s also clear that the oncology community are concerned as to whether DCIS really is cancer or a possible pre cancer. In other words: lots and lots and lots of doubts.

Is the best response to remove both breasts – both the affected breast and the unaffected one? I’d be surprised if this would be offered on the NHS. It begs the question about how far we should go with trying to prevent disease using surgery – should we remove our ovaries and wombs too, ‘just in case’, even when the organs are healthy and we are at normal genetic risk of developing disease?

There’s an problem in that doctors may be asked to perform procedures which are unnecessary, but where a ‘customer’s’ rights holds trump. This may be fine as long as there are no wound infections, post operative deaths, or mental health sequelae. But of course there are, and the history of medicine doing harm is long and humbling. The other massive threat is to medical professionalism; the need to do what is based on evidence rather than balance sheets. This excellent article from Boston, by Arnold Relman, says it clearly; “ The vast amount of money in the US medical care system and the manifold opportunities for physicians to earn high incomes have made it almost impossible for many to function as true fiduciaries for patients.”

As the NHS begins to be fractured, and people are encouraged to shop around for what they consider best, I’m concerned that the guidance from NICE is going to be usurped by offers of overtreatment. It’s easy to think that more treatment must be better and to blame NICE for rationing, rather than deliverers of the evidence. For who are patients to believe? The bottom line is that patients should be able to believe professional doctors. But, as Relman asks, do  doctors whose bottom line is an accountancy balance sheet merit that trust?

Inside Health – choirs are good for you

Here are the references – it will be up here probably tomorrow.

http://www.ncbi.nlm.nih.gov/pubmed/22495689

 

http://www.ncbi.nlm.nih.gov/pubmed/9783861

 

http://www.bmj.com/content/314/7086/1037

 

http://onlinelibrary.wiley.com/doi/10.1002/hec.1242/abstract;jsessionid=3D0C17206FD3C96227DFD224D616F5FA.d02t03

 

http://www.oecd.org/dataoecd/40/24/45760738.pdf

 

http://onlinelibrary.wiley.com/doi/10.1002/hec.1242/pdf

 

http://www.york.ac.uk/res/herc/documents/wp/11_21.pdf

 

http://www.bmj.com/content/313/7072/1577?view=long&pmid=8990990

 

http://www.biomedcentral.com/content/pdf/1471-2466-10-41.pdf

Medicine and the Media – strep B in pregnancy

is in the BMJ here

Pod delusion transcript

 

From here, since my self-created recording is so bad.

 

Last week, Georgia Gale Grant argued that, rather than praying for the recovery of Fabrice Muamba, it would be better, for humanists, sceptics and aethists,  if aged between ‘14 and 35’ to ‘ get regular ECGs to make sure you’re not at any known risk of sudden death’ – and she recommended that you get your friends or children or other relations to go too.

 

On the first point; I agree. One study in the American Heart Journal from 2006 suggested that prayer didn’t help heart bypass patients recover better.

 

But what’s the evidence for her other suggestion – screening a chunk of the population with an ECG – that is, an electrocardiogram – colloquially known as a heart tracing, and obtained by attaching electrodes to the limbs and chest wall.

 

What she’s suggesting is a screening test. Unfortunately, screening is messy, may be counter-intuitive, and is sometimes hazardous. Screening tests are not for people with symptoms. Someone who has chest pain, for example, is not given an ECG as a screening test, but a diagnostic test. They are very different, but often confused, not just by citizens, but politicians and even healthcare professionals. But the difference is crucial. Screening is looking for disease before the person knows they have it.

 

There’s a great book by Angela Raffle and Muir Grey, called ‘Screening – Evidence and Practice.’ She is a public health doctor, he was the Director of NHS Screening. It starts “All screening does harm. Some do good as well and, of course, some do more good than harm at a reasonable cost’.

 

So what are the harms of screening? It seems so sensible, so logical – pick up disease early, fix problems before you get complications – doesn’t it? The truth is that screening is rarely so straightforward. Chapter and verse on what makes a great screening test was published by the World Health Organisation by Wilson and Junger in 1968.

I’ll put a link on my website to it – for this document is full of clarity. For example, they decreed that screening should look for important conditions for illnesses where the natural progression of the disease was understood.

Early treatment should have extra benefits compared to later treatment, and the test should be acceptable with the risks, physical and psychological, being less than the benefits.

 

Some screening tests come with high benefits and small risks. For example, all newborn babies in the UK are screened for the rare genetic condition PKU, phenyl ketone uria. If the child is diagnosed soon after birth, he or she can avoid foods containing phenylalanine and avoid the brain damage that would otherwise occur. It’s a rare condition – 1 in 10 000 births – but because there is a good preventative treatment – avoiding certain foods – that can be recommended  – it’s generally thought of as a pretty good screening test. The false positive rate is about 5%, meaning that of every 20 babies with a positive result, one is wrong. False negatives seem very uncommon.

And this is why all children born in the UK have a heelprick test at about 10 days old, which includes a PKU screen. The harms are in false diagnosis – but this is minimised by re-testing, and, of course, the heels of all new born babies have to be pricked with a needle to pick up the small amount with problems.

 

But this is a validated, well researched and audited screening test. Not every screening test on offer comes with the same balance of risks. You may have noticed the panoply of high street clinics offering health checks, or adverts on TV offering CT scans as ‘peace of mind’,  or you may have had – like me – letters through the door encouraging me to attend a church hall near me for a heart tracing, cholesterol testing, ultrasound of the neck or abdominal aorta for a few hundred quid. (I think I have an article in this week’s BMJ about this – I’ll link it

online.) Again, it sounds sensible, responsible, logical.

Catch it early! Why would you want to be ignorant of your ‘risks’? And indeed, in the USA, where they seem to love health screenings, regular medicals drive a huge amount of testing both on Medicaid  and with doctors in the paid-for arena, working to commission.

 

But how much of this does any good? We have to remember those Wilson and Junger criteria. There is no point picking up a problem that you can’t do something useful about. Let’s take ultrasound of the carotid arteries, in the neck, for people who are well, as offered by many private screening clinics. The idea is that you can find vascular disease and treat it before it causes a stroke.

The problem is that in order to prevent a stroke, the surgery offered is carotid endarterectomy – which corrects the narrowing. However, because the death rate from the operation is, relatively speaking high – about 3% – the potential small drop in stroke rates achievable because of the operation doesn’t provide a good risk benefit ratio.

So that’s why both the UK National Screening Committee and the US Preventative Services Task Force say it does more harm than good – and it’s not a recommended screening test.

 

The other problem that screening produces is to identify conditions that would have never caused a problem during that person’s lifetime. One clear example is breast screening. This is an xray of the breasts taken every 3 years, in the UK, for women from age 47. The Cochrane review – that is, an independent review of all the information on the subject – concluded that 2000 women are needed to be screened for 10 years to prevent one death from breast cancer. But to get this reduction, 10 other women have to be treated with surgery radiotherapy or chemotherapy for a breast cancer that would never have affected them in their lifetime. This is ‘overdiagnosis’ – cancers diagnosed and treated but which would never have maimed or killed.

 

In medicine, a clear distinction between normal and abnormal doesn’t always exist. One of my deep concerns is that the dilemmas and uncertainties of screening tests aren’t adequately communicated to the people taking them up. There’s an excellent NHS resource for men considering PSA screening, for example, which is used to detect prostate cancer – but which explains that there is no evidence that PSA screening reduces overall death rates, and that treatment can result in impotence and incontinence. But we don’t get the same aid for the other screening tests the NHS offers, and I am afraid this results in a rosy depiction of screening which is, sadly, illusory.

 

So what about cardiac ECG screening?; well. There has actually been a lot of work on it. It’s clear that ECG screening doesn’t benefit adults with no symptoms – the test doesn’t usefully or reliably pick up abnormalities.

For young people, contrary to the actions  Georgia suggested, the National Screening Committee in the UK doesn’t recommend screening.

 

Why? There are several causes of cardiac death in this group, including abnormalties in the conduction system of the heart, for example, long QT syndrome, and heart muscle problems, such as the cadiomyopathies. A good screening test would pick up all these abnormalities, with no false positives; and it would also mean that effective treatment was available.  The result would also come with meaning – there is no point picking up a ‘problem’ if it only rarely would lead to future problems. You have to know that an ECG abnormality really is abnormal. And a good test would not let abnormal hearts slip through the screening. And what do we know?

 

Less than  1 in 100 000 young adults die of sudden cardiac death per year. Per 100 000 screened with an ECG, you would expect to find 300 with a cardiac problem, of whom

30 would be ‘at risk’, and of whom 0.4 would die per year.

The screening would also generate at least 2,500 abnormal ECGs – possibly double that – and 150 false negatives. For children with certain cardiac abnormalities, medication can help to reduce risk – but there is no such thing as a guaranteed peace of mind. Not all complications could be prevented. The harms would include telling a large proportion of people that they had an abnormality – but the vast majority would never come to harm from  it. And about half of ‘at risk’ children would not be picked up – in other words, false reassurance.  Many other children would be medicated – or told they had a potentially fatal condition – when the chances were actually very favorable for them never to have an cardiac arrhythmia. Harms can be overt but also subtle – this is the kind of thing that GPs see. And of course, there’s a cost-effectiveness argument too – is this the best way that money can be spent to improve children’s health?

 

Like I said, screening is complicated. It comes with numerous caveats and is never a benign act. It’s worth remembering too, the ‘popularity paradox’ – the worse a screening test it, the more false positives you generate, and the more people believe that their lives were saved – when actually, by being diagnosed wrongly, they were potentially harmed, not helped. Screening needs science and attention to the evidence – even when it tells you things you’d rather not know.

Women’s Hour – cervical screening

 

Here are some of the references used in Women’s Hour today.

There was not enough time to discuss the stats properly. What is crucial is the fact that there is a lot of guess work – there has (shockingly) never been a proper RCT of cervical screening in normal risk women. So all estimates involve some guesswork, or modelling. (Archie Cochrane famously said of cervical screening that there has been “never has there been less appeal to evidence and more to opinion”).

Have a look at the 13 minute video on cervical screening http://www.cancerscreening.nhs.uk/cervical/publications/its-your-choice.html (with approx 10 seconds devoted to false positives, less to overtreatment) and compare with the prostate cancer screening decision aid http://www.prosdex.com/index_content.htm.

Men are given numbers, pros and cons, and offered an informed choice – women are given platitudes about yoga, green tea and chocolate cake. The cervical screening leaflets do not spell out the risks of overtreatment and the potential cervical effects and association with preterm birth.

Repeat: I am not against screening per se. I am opposed to unthinking screening, to doctors paternalistically herding women into getting screened, and women being denied and informed and honest choice.

Bristol cervical screening incidence and screening reductions

http://www.bmj.com/content/326/7395/901

 

Risk factors for cervical screening

http://cancerhelp.cancerresearchuk.org/type/cervical-cancer/about/cervical-cancer-risks-and-causes

Debate on cervical screening

http://www.bmj.com/content/315/7113/953.full

http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(04)17260-7/fulltext

http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(98)21007-5/fulltext

Incidence of cervical cancer over time

http://www.ons.gov.uk/ons/rel/cancer-unit/cancer-trends-in-england-and-wales/smps-no–66/index.html (fig 6.7, page 51)

Stats on cervical cancer incidence in the UK

http://info.cancerresearchuk.org/cancerstats/incidence/commoncancers/uk-cancer-incidence-statistics-for-common-cancers

Incidence and mortality of cervical cancer in nordic countries

http://www.biomedcentral.com/1471-2407/11/240/figure/F1?highres=y

http://www.biomedcentral.com/1471-2407/11/240

Incidence cervical cancer in different countries

http://info.cancerresearchuk.org/cancerstats/types/cervix/incidence/

Women's Hour – cervical screening

 

Here are some of the references used in Women's Hour today.

There was not enough time to discuss the stats properly. What is crucial is the fact that there is a lot of guess work – there has (shockingly) never been a proper RCT of cervical screening in normal risk women. So all estimates involve some guesswork, or modelling. (Archie Cochrane famously said of cervical screening that there has been "never has there been less appeal to evidence and more to opinion").

Have a look at the 13 minute video on cervical screening http://www.cancerscreening.nhs.uk/cervical/publications/its-your-choice.html (with approx 10 seconds devoted to false positives, less to overtreatment) and compare with the prostate cancer screening decision aid http://www.prosdex.com/index_content.htm.

Men are given numbers, pros and cons, and offered an informed choice – women are given platitudes about yoga, green tea and chocolate cake. The cervical screening leaflets do not spell out the risks of overtreatment and the potential cervical effects and association with preterm birth.

Repeat: I am not against screening per se. I am opposed to unthinking screening, to doctors paternalistically herding women into getting screened, and women being denied and informed and honest choice.

Bristol cervical screening incidence and screening reductions

http://www.bmj.com/content/326/7395/901

 

Risk factors for cervical screening

http://cancerhelp.cancerresearchuk.org/type/cervical-cancer/about/cervical-cancer-risks-and-causes

Debate on cervical screening

http://www.bmj.com/content/315/7113/953.full

http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(04)17260-7/fulltext

http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(98)21007-5/fulltext

Incidence of cervical cancer over time

http://www.ons.gov.uk/ons/rel/cancer-unit/cancer-trends-in-england-and-wales/smps-no–66/index.html (fig 6.7, page 51)

Stats on cervical cancer incidence in the UK

http://info.cancerresearchuk.org/cancerstats/incidence/commoncancers/uk-cancer-incidence-statistics-for-common-cancers

Incidence and mortality of cervical cancer in nordic countries

http://www.biomedcentral.com/1471-2407/11/240/figure/F1?highres=y

http://www.biomedcentral.com/1471-2407/11/240

Incidence cervical cancer in different countries

http://info.cancerresearchuk.org/cancerstats/types/cervix/incidence/

Pod delusion references

 

 

 

 

 

 

Here are the references for a piece on the Pod Delusion podcast last week. The dreadful quality of the recording is all my fault.

 

http://www.ncbi.nlm.nih.gov/pubmed/16569567

 

http://www.amazon.co.uk/Screening-Evidence-practice-Angela-Raffle/dp/0199214492

 

http://whqlibdoc.who.int/php/WHO_PHP_34.pdf

 

newbornbloodspot.screening.nhs.uk/getdata.php?id=11648

 

http://www.scielo.org.ar/pdf/rac/v76n2/en_v76n2a20.pdf

 

 

http://www.screening.nhs.uk/cms.php?folder=2898

 

http://www.annals.org/content/147/12/854.full

 

http://summaries.cochrane.org/CD001877/screening-for-breast-cancer-with-mammography

 

http://www.nhsdirect.nhs.uk/decisionaids

 

http://www.screening.nhs.uk/hcm#mce_temp_url#

 

 

 

http://www.nejm.org/doi/full/10.1056/NEJMoa070972

 

http://content.onlinejacc.org/cgi/content/abstract/42/11/1959?ijkey=cebf4fab66fd658832c7246124a4530c77eab366&keytype2=tf_ipsecsha

Inside health and cycle helmets

The references I used for Radio 4′s  Inside Health are here

 

http://aje.oxfordjournals.org/content/165/12/1343.abstract

http://www.bmj.com/content/343/bmj.d4521

http://www.nejm.org/doi/full/10.1056/NEJM198603063141003

http://aje.oxfordjournals.org/content/165/12/1343.abstract

http://www.thecochranelibrary.com/userfiles/ccoch/file/Safety_on_the_road/CD001855.pdf

http://ehp03.niehs.nih.gov/article/info%3Adoi%2F10.1289%2Fehp.0901747

http://www.dot.state.fl.us/research-center/Completed_Proj/Summary_RD/FDOT_BDK82%20977-01_rpt.pdf

http://injuryprevention.bmj.com/content/13/3/190.full

http://www.sciencedirect.com/science/article/pii/S0001457506001540

 

http://drianwalker.com/overtaking/overtakingprobrief.pdf

http://www.eta.co.uk/2011/04/01/safest-bicycle-helmet-has-built-wig