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Routine breast cancer screening can do "more harm than good" and women who missed appointments should "carry on with their lives", doctors have said.

A group of 15 health experts have written to the Times, saying women must not be subjected to "fear-mongering".

It comes after 450,000 women in England were not invited for routine screening because of a computer error.

Breast cancer charities say the screening programme offers women the "best chance" of early detection.

'No impact'

In the letter to the newspaper, the group of academics and GPs say women aged 70-79 who are being offered catch-up appointments should only seek help if they notice a lump or other symptoms.

"[They] would be well advised to look this gift horse in the mouth," the medical professionals wrote in the newspaper.

"The breast screening programme mostly causes more unintended harm than good, which is slowly being recognised internationally.

"Many women and doctors now avoid breast screening because it has no impact on all-cause death."

The claims of lives saved because of breast screening are counteracted by deaths resulting from interventions, the medics said.

And the most dangerous and advanced cancers are not prevented by screening programmes, they said.

The letter added: "Although counter-intuitive, catching some things that look like cancer down a microscope (before it exists) can be too early and unnecessary."

Among those who have signed the letter are Susan Bewley, professor of women's health at King's College London, and Michael Baum, professor emeritus of surgery at University College London.

The error, which dated back to 2009, was revealed earlier this week. Up to 270 women in England may have died because they did not receive invitations to screening.

The 309,000 women affected - those who are still alive - will be contacted by letter by the end of May, with the offer of catch-up mammograms.

'How dare they'

The NHS estimates that its screening programme saves about one life for every 200 women who are scanned for breast cancer, adding up to about 1,300 lives saved each year in the UK.

But about three in every 200 women screened are diagnosed with a cancer that would never have become life-threatening, equating to about 4,000 women each year being offered unnecessary treatment.

Retired nurse Maggie Whyte, 61, from Edinburgh discovered she had stage one breast cancer when she went for a routine mammogram last year.

"I was lucky as it hadn't spread to my lymph nodes," she said. The treatment she underwent - a lumpectomy and radiotherapy - was successful.

"It could have been so different," she said. "Another three years, I don't know what would have happened.

"How dare they say screening is no good? I am so grateful to have my health."

'Two sides to the coin'

Fiona Hazell, of charity Breast Cancer Now, said it is "absolutely right" that PHE is offering catch-up appointments.

The screening programme is the "best chance" of breast cancer being detected at an "early, more treatable stage", Ms Hazell said.

Dr Emma Pennery, clinical director at Breast Cancer Care, agreed that screening "remains our best tool" for detecting breast cancer early, but added: "There are two sides to the coin and it's estimated that for every life saved, three women will have unnecessary treatment."

She added it is "crucial" that every woman eligible is offered screening and is given information about risks and benefits to make their own choice.

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Meanwhile, Sara Hiom at Cancer Research UK, said women can be "reassured" that the impact of the error is "likely to be significantly less than the worst-case scenario predictions".

"Screening has harms as well as benefits and, while an unknown number of women will have missed the opportunity to have their breast cancer diagnosed earlier by screening, others will have avoided treatment that would not have extended their lives," she said.

"It's also helpful to remember that 72% of breast cancers are diagnosed by women finding a lump or noticing other symptoms themselves, so screening is not the only way of discovering something is wrong."

Age-specific advice

Breast cancer screening is automatically offered once every three years to women aged 50 to 70 in the UK.

Public Health England (PHE) says it was not aware of the national problem with the screening programme until January.

On Saturday, PHE said it would make further support available to women aged over 72 so they can understand the potential benefits and harms of screening later in life.

Dr Jenny Harries, PHE's deputy medical director, said: "All of our actions are based on the best available clinical advice...

"We are aware of the debate and evidence of screening in older women and we know it can lead to over-diagnosis, which is why we have published a new advice leaflet specially for women over 70."

Announcing the computer error earlier this week, Health Secretary Jeremy Hunt acknowledged there is "currently no clinical consensus about the benefits of screening" for the 68-71 age group.