Breast screening, overdiagnosis and some denial

There was another publication on the unintended consequences of mammography last week, so off I went to look at it. Ha! Bless those Scandewegians. Who knew they’d  turn out to be so much trouble on breast screening? Norwegians this time. It’s been Danes. They host the Nordic Cochrane Group in Copenhagen who stirred things up in the past, questioning just what on earth breast screening is doing to women.…..

In case you want to follow my route I went to Overdiagnosis of Invasive Breast Cancer Due to Mammography Screening: Results From the Norwegian Screening Program by Mette Kalager, MD; Hans-Olov Adami, MD, PhD; Michael Bretthauer, MD, PhD; and Rulla M. Tamimi, ScD Ann Intern Med. 2012;156:491-499.

The objective of the paper was to estimate the percentage of overdiagnosis of breast cancer attributable to mammography screening.

Good oh. Got that.

The conclusion of the paper was that mammography screening entails a substantial amount of overdiagnosis.

O dear. How substantial was substantial? 15-25% of women screened, apparently.  So, up to 1 in 4 screened women could be getting unnecessary surgery, radiotherapy, chemotherapy and psychic trauma, alongside their diagnosis through screening. The authors made a big effort to ensure they were looking solely at over diagnosis of invasive cancer. I suppose the estimate of harm to women through over diagnosis would have been even greater had they included diagnoses of Ductal Carcinoma in situ in their sums.

The authors final sentences were “… overdiagnosis and unnecessary treatment of nonfatal cancer creates a substantial ethical and clinical dilemma [my italics] and may cast doubt on whether mammography screening programs should exist. This dilemma can be reduced only when potentially fatal cancer that requires early detection and treatment can be reliably identified. Until then, women eligible for screening need to be comprehensively informed about the risk for overdiagnosis. [more of my italics]”

The BBC, amongst others, reported the paper.

So then I wondered what high profile breast cancer charity Breakthrough Breast Cancer thought. They’ve got 'previous', not apparently understanding how screening works in general, or what the issues are in breast screening, in particular. My disquiet boils down to their casual attitude to the importance of informed choice by women. As I expected, I was not pleased.   

On their media pages it says

“Routine mammograms may result in breast cancer over-diagnosis”


“Breakthrough Breast Cancer responds to a study published in the Annals of Internal Medicine which suggests that routine breast screening could result in significant overdiagnosis.

03 Apr

The Policy Manager at Breakthrough Breast Cancer says: “The rate of over-diagnosis in breast cancer screening has been debated widely and led to confusing messages for women on the effectiveness of breast screening.  However, we believe that screening is vital as it helps detect breast cancer early when treatment options are likely to be less aggressive and have more successful outcomes.
The National Cancer Director has commissioned an independent review of all the evidence that underpins the NHS Breast Screening Programme and we expect this will soon provide clarity on this issue.”

Firstly: The paper was called Overdiagnosis of Invasive Breast Cancer Due to Mammography Screening: Results From the Norwegian Screening Program.

Breakthrough managed to summarise this as “Routine mammograms may result in breast cancer over-diagnosis”. And  “…suggests that routine breast screening could result in significant overdiagnosis.”

The paper didn't show mammograms may result in overdiagnosis. They do. The researchers went a stage further and tried to quantify it.

The paper did not ‘suggest' overdiagnosis might be a consequence of screening – overdiagnosis is already a known risk. The problem is coming to some consistent measure of 'how much', which is why they did the research and published their analysis.

Secondly: I do agree with Breakthrough’s first sentence but then the rest goes downhill.

We’re back with assertion in the place of reasoning; there's no engagement from Breakthrough with what is known or suspected on overdiagnosis. This is not honest. The public already powers quite a lot of opinion through ‘belief’ already, without a scientific and research organisation such as Breakthrough lobbing in ‘beliefs’ as a way to deal with the complexity of screening, instead of a reasoned appraisal of risk and benefit. Scientists know a lot about uncertainty and ambiguity but somehow going for that that balance bores the pants off Breakthrough’s Press Office who draft copy about benefit as if that is the only side of the story. Any lay person could come up with that on their own, unaware of the real complexity.

Are the Press Office, or the policy people in their organisation really unaware that there are always risks, in any screening context?

Thirdly: I am intrigued by the idea that Breakthrough expect clarity from the review. I hope so too, but with anything other than a total agreement from the breast cancer charities with whatever the report says, we aren’t going to get it. Media demand for an alternate critique won't ask for a objective reading of the evidence. They will want a media friendly subjective reading based on the views of women who already have with breast cancer. The breast cancer charities will oblige. 

These women are not the target population for screening. They do not have to make an informed choice for screening in the future. Indeed, they probably didn't in the past, now I come to think of it.

Breakthrough is a campaigner for improved screening. That’s fine, of course we’d all like improved screening but one of the improvements currently required is better information on the risks and benefits of breast screening which doesn’t seem to be on their agenda. This evidence should emerge from the current Review of breast screening. Another improvement would be technology and its careful application to reduce the numbers of women who imagine they experience the ‘benefit’ of breast screening - an early diagnosis and treatment - but actually what they land up with is the big risk – unneeded treatment that won’t save their life because their life is not in danger. We can’t bimble along as we do at present, creating more women 'blissfully' ignorant of the possibility that they have been lumbered with a diagnosis with little or no likely biological consequence, but with shocking life-long effects as a result of its needless sorting out.  

Breast screening is a health service aimed at well women and it should work as well as it can for all invited to step up to the machine, whether they turn out to have cancer, or not, or have something in between. The huge public health programme of breast screening is not solely about the saving of women’s lives from cancer; there is just as much ethical obligation to adequately inform women, promote choice, and advise women about balancing the risk and benefits of screening.

I am very keen on women and informed consent, choice and decision making. By not addressing risks in a relevant media release and comment Breakthrough apparently doubts women’s capacity to give, make or take such action.

There was an editorial commentary in the same edition of the journal by Joann G. Elmore, MD, MPH University of Washington School of Medicine, Seattle. Suzanne W. Fletcher, MD Harvard Medical School and Harvard Pilgrim Health Care Institute Boston Overdiagnosis in Breast Cancer Screening: Time to Tackle an Underappreciated Harm Ann Intern Med. 2012;156:536-537.

“Instead of focusing on the exact extent of over diagnosis, it is time to agree that any amount of over diagnosis is serious and to start dealing with this issue now. Ultimately, better tools are needed to reliably identify which breast cancer will be fatal without treatment and which can be safely observed over time without intervention, but we cannot wait for these tools to be developed.”

Elsewhere in the editorial they write… “.... we have an ethical responsibility to alert women to this phenomenon. Most patient-education aids do not even mention over diagnosis, and most women are not aware of its possibility. Effective communication about over diagnosis of breast cancer will require great care—and evaluation to determine how best to do it; otherwise, women may become fearful or angry. Just because communicating with patients will be difficult does not mean that we should not tackle this problem. Informed women deserve no less when deciding about breast cancer screening.[My Italics]

What do you think of that, Breakthrough? Should we engage women in a difficult conversation or just pretend there isn’t one?

Not all charities are this cockeyed. What does CR-UK say? There’s nothing I can find direct from their site but they may have conflicts of interest that need managing – this is right, by the way, not an accusation of evasion. They are helping deliver the current review of breast screening.

They did chat to the BBC and on their website it says

Dr Julie Sharp, Cancer Research UK's senior science information manager, said: "Cancer Research UK is working with the National Cancer Director on an independent review of breast screening.

"Women need more accurate, evidence-based and clear information to be able to make an informed choice about breast screening. The decision whether to be screened is a personal one and that decision should be made with all of the potential harms and benefits fully explained.

"Until we have the results of the review, Cancer Research UK's position is that we remain supportive of breast screening."

Yep. I go along with that. Well, except inasfar as I’ve already turned down breast screening but that was a personal decision, wholly right for me, not one I’m recommending to anyone else. Your own your own, pal, working that one out! CR-UK’s take is exactly the right one as a holding position until we know more, IMHO. If this is a current concern you can probably delay a mammogram for three months, to await the results.... and then decide. 

Why couldn’t Breakthrough manage some response like that, instead of an assertion of their belief in the effectiveness of screening? In any case, the paper they were commenting on was not about effectiveness, it was quantifying risk in one of the 'effects'. Breakthrough gave the politician’s response, most assuredly not a compliment, trotting out an answer to a question that was not being asked.

Breakthrough can’t be expecting the status quo on the outcome for the screening programme review, surely? The minimal likely recommendation is more and better information for women on the risks of screening. Breakthrough will have to start talking about them, then. Even if the evidence base does suggest the UK breast screening programme should scrapped (unlikely) or severely curtailed Breakthrough really needn’t worry. It ain’t gonna happen. Neither party in the Coalition would risk it. Nor Labour. All those women voters at the next election? Much as I crave evidence based policymaking, it isn’t for realists.

I do hope though, at the very least we land up with a breast cancer equivalent of the Prostate Cancer Risk Management Programme’s thorough information materials about the PSA test and prostate cancer – the first time prostate cancer will have taught the breast cancer sector something.

We’ll see. We'll see.....


Informed consent? What's that....

It has always astounded me the complete lack of respect for informed consent in women's cancer screening and cervical screening "always" escapes close scrutiny. Both programs seem to do as they please with no regard for proper ethical standards or our legal right to make an informed decision, it contrasts sharply with prostate cancer screening.
We're expected to do as we're told in complete ignorance or after accepting the "screening story" and if we have any doubts or choose not to screen, we're often verbally attacked and harshly judged...labelled immature, irresponsible, uneducated, lower class etc - we have all the studies that ponder why some women don't have pap tests...umm, it's an elective screening test, but how many studies do we have on the risks - how many women endure unnecessary cone biopsies? How many premature babies are born as a result of over-treatment causing cervical incompetence? Very little research there...and only one study that showed the lifetime risk of referral for colposcopy and usually some sort of biopsy here was a huge'd think that would prompt debate, more research and changes to the program...No way....silence and a figure never released to women.
Now all of this worry and harm is for a cancer with a 0.65% lifetime risk.

I have never understood how they get away with it and even today, there is no critical discussion in Australia - cervical screening is untouchable and with breast screening - everyone has remained silent, except for the brave Assoc Prof Robin Bell who warned women last year about over-diagnosis and uncertainty of benefit. She has been completely ignored - no response from the Govt and no doctors have stepped forward to support her.

The cat however is out of the bag with mammograms, thanks to the internet and more women are declining breast screening - the target of 70% of those 50 to 69 is fading fast. I hear there is talk of paying doctors financial incentives to get their patients into breast screening centres - which currently happens with pap testing - the target for the latter was recently increased to 70% - in response to a 2% fall in pap testing rates. Great news when you know we are some of the most over-screened and over-treated women in the world - no woman needs an absurd 26+ pap tests - hopefully, more women are getting to the facts. So much for medical ethics, when it comes to women anyway...

Honestly, I despair for those who just accept the order to screen or accept the material in the brochures or their doctor's advice...thank heavens, I took the time to look into these programs. I can't see things changing much here...with no advocates for informed consent these programs have a free reign.

Thanks for a great piece of writing - such a nice change to the insulting rubbish and slogans usually directed at women in place of real information.
It is impossible for any woman to give informed consent when we're provided with misleading/biased and incomplete information.....but no one seems to care.

If you google informed consent and cervical screening and specify Australian sources - nothing appears...exactly! There is a little more on breast screening, but most things are locked inside medical journals that require a subscription...once again, the internet and Prof Baum, Gilbert Welch, Peter Gotzsche and others have come to the rescue there.