Spotting cancers: But do mammograms save lives?

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BBC News HEALTH New concerns over breast screening Subject:

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HEALTH New concerns over breast screening. htm

 

- http://news.bbc.co.uk/hi/english/health/newsid_1607000/1607113.stm -

 

 

 

New concerns over breast screening

Spotting cancers: But do mammograms save lives?

 

A fresh row has broken out over controversial claims that screening for

breast cancer may not actually be saving lives.

The research was first published last year, but has been re-examined

following a series of protests from cancer organisations over the findings.

Now one of the world's leading medical journals, The Lancet, agrees that

there is not enough evidence from large-scale trials to support breast

screening.

However, cancer charities and the UK cancer screening programme disagree

strongly with their verdict.

At present, there is no reliable evidence from large randomised trials to

support screening mammography programmes

 

Richard Horton, Editor, The Lancet

All UK women aged between 50 and 64 are currently offered screening once

every three years.

It is hoped that tumours may be spotted earlier, making treatment more

likely to provide a cure.

Currently, it is reckoned that as many as 300 lives are saved a year by

breast screening - and more recent estimates suggest this annual figure is

climbing rapidly.

However, two Danish researchers from the Nordic Cochrane Centre in

Copenhagen have re-examined the seven large-scale studies looking into the

effectiveness of breast screening.

They say that the studies which support breast screening are either flawed

or weak, with the only two high quality studies showing no benefit at all.

In addition, they suggest that screening may result in women receiving more

aggressive treatments for cancer, increasing the number of mastectomies by

approximately 20%.

They write, in The Lancet: " We hope that women, clinicians and policy-makers

will consider these findings carefully when they decide whether or not to

attend, or support screening programmes. "

Flood of criticism

The Danish pair, Peter Gøtzsche and Ole Olsen, first voiced these criticisms

last year, and provoked a flood of protest as a result.

In the light of this, they say, they have thoroughly reviewed their work -

and reached the same conclusion.

" We found the results confirmed and strengthened our original conclusion, "

they wrote.

However, cancer organisations in the UK have repeated their attacks on the

conclusions.

 

 

We found the results confirmed and strengthened our original conclusion

 

Peter Gøtzsche and Ole Olsen, report authors

Many are worried that any adverse publicity about breast screening will

dissuade women from coming forward.

Stephen Duffy, an expert in breast screening from the Imperial Cancer

Research Fund, said that the five studies which supported the use of

mammograms should not have been excluded.

He said: " Studies in the UK and Sweden by ICRF and others have shown breast

cancer screening substantially reduces women's risk of dying of breast

cancer.

" Research published only in May demonstrated that women who attend regular

breast screenings may reduce their risk of dying by more than 50%. "

Disagreements

A spokesman for the UK Breast Screening Programme agreed: " The way Gøtzsche

and Olsen classified studies was based on criteria that would not be agreed

by many experts in the field.

 

 

Studies in the UK and Sweden by ICRF and others have shown breast cancer

screening substantially reduces women's risk of dying of breast cancer

 

Stephen Duffy, Imperial Cancer Research Fund

" Indeed many researchers would classify all seven studies as of similar

quality, and when the results from all seven studies are combined, there is

clear evidence of the benefit from mammography. "

If existing studies are too weak to support the use of breast screening,

then the chances of organising large-scale replacements are slim, as these

would have to involve a sizeable " control " sample who would not be screened

for the purposes of comparison.

As most clinicians already feel that breast screening offers a significant

benefit, it would probably be felt ethically unsound to leave so many women

without it.

However, the fact that The Lancet now backs the Danish team is a significant

move in supporting those who question the benefits of breast screening.

Editor Richard Horton wrote: " Women should expect doctors to secure the best

evidence about the value of screening mammography.

" At present, there is no reliable evidence from large randomised trials to

support screening mammography programmes. "

Professor Michael Baum, from the Portland Hospital in London, says that it

is now right that women should be presented with all the evidence about

screening before they give their consent.

He said: " Even with the most optimistic estimates on saving lives, you would

still have to screen 1,000 women for 10 years to save one life.

" If you have one significant adverse event which costs a life in this group

over this period, all that benefit is cancelled out.

" The Lancet is a highly influential journal and if they are backing this

review, it's highly significant. " WATCH/LISTEN

 

ON THIS STORY

 

The BBC's Karen Allen

" The scientists are being backed by one of the most respected medical

journals "

Cancer surgeon Professor Michael Baum

" The statistics have to be taken very seriously "

On the BBC's Today programme:

Ole Olsa, one of the authors of the report, and Julietta Patnick of the NHS

screening programme