PARIS: The benefits of preemptive breast cancer screening outweigh the risks,
a study said Tuesday, insisting the practice saves thousands of lives.
The new research adds to the
debate about the dangers of overdiagnosis, which sees some women undergo
invasive treatment for cancers that would never have made them ill or even been
diagnosed were it not for the scans.
"Breast screening extends
lives," concluded a panel of researchers in The Lancet medical journal.
The team had analysed data from
other trials conducted over many years in Britain, where women aged 50 to 70
are invited for a screening mammogram every three years.
The data, it said, pointed to a
20 per cent reduction in mortality -- or one death prevented for every 180
women screened.
This meant that the UK screening
programmes "probably prevent about 1,300 breast cancer deaths every
year," said the report.
But there is a cost.
Nearly 20 per cent of breast
cancer diagnosed by screening would never have caused any problems, said the
study.
The panel, set up to advise
British policymakers, estimated that among every 10,000 women invited to
screening from the age of 50 in the Britain, 681 cancers would be discovered,
of which 129 would be overdiagnoses, and 43 deaths prevented.
The report showed that "the
UK breast-screening programme extends lives and that, overall, the benefits
outweigh the harms," The Lancet wrote in an editorial.
"Women need to have full and
complete access to this latest evidence in order to make an informed choice
about breast cancer screening."
The team conceded there were
limitations to its work, including that all the data scrutinised was more than
20 years old.
Cancer experts have been at
loggerheads for years about whether the benefits of screening outweigh the harm
of overdiagnosis.
All cancer, once picked up in the
screening process, is treated, often with surgery as well as radio- and
chemotherapy, as it is impossible to tell which growths would have remained
undetected for the remainder of a woman's life.
In August, medical experts Steven
Woloshin and Lisa Schwartz wrote in the British Medical Journal (BMJ) that
screening only narrowly decreased risks that a 50-year-old woman would die from
breast cancer within 10 years -- from 0.53 per cent to 0.46 per cent.
Up to half of women screened
annually over 10 years experienced at least one false alarm that required a
biopsy, they said.
And in 2010, a report in the New
England Journal of Medicine said mammograms have only a "modest"
impact on reducing breast cancer deaths.
The latest panel had been created
by the national cancer director for England, Mike Richards and Cancer Research
UK chief executive officer Harpal Kumar.
Its work, said The Lancet,
"should begin to lay the benefits versus harm controversy to rest".
- AFP/ck
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