The oft-quoted figure - that one woman in 12 in the UK will develop the disease - is off target and only applies to women aged over 75, they say.

The doctors add that the US figure of one woman in eight only applies to women who live to 80.

The findings appear in the British Medical Journal.

The authors call for the risk of breast cancer to be put in perspective because if women focus to strongly on breast cancer they ignore "far more serious health threats".

'Misleading' posters

Dr John Bunker, of the joint University College London Medical School-Cancer Research Campaign clinical trials centre, is lead author of the study.

The awareness campaign may cause alarm

He said he and his colleagues first became interested in the field following the appearance of posters for Breast Cancer Awareness Month in October.

They said that one women in 12 in the UK is affected by breast cancer.

"Now, that's correct if a woman lives to be 75," Dr Bunker said.

"But we're concerned that young women are apt to be frightened by this information."

He said that this manifested itself by people getting screened for cancer when it was of little use to them.

In the US, he said, two-thirds of mammographies - scans to detect signs of breast cancer - were performed on under-50s.

No clinical evidence suggests these were beneficial among such a young age-group, he added.

'Perpetual pitch'

Professor Gordon McVie, director general of the Cancer Research Campaign, which funded the research, agreed.

"We have just lived through a month of breast cancer awareness where the perpetual pitch was to young women with the implication that they were likely to get breast cancer, which is a total fallacy," he said

He said that young women are not at risk of breast cancer unless they have a genetic trait that puts them at risk.

"It's scaremongering," he said, and added that the proof of the effectiveness of the campaign was the number of young women attending mammography screenings.

Professor McVie said it was "a total nonsense" that women should attend such screenings before they were 50.

"Breast cancer is a disease of the elderly," he said.

"It is only a young woman's issue in that they should adopt a healthy lifestyle, exercise and a good diet to stop them getting cancer in their 60s."

Lower risk

In reality, the risk of developing the disease was much lower than those regularly quoted and depended on age.

Of all deaths, breast cancer was the cause of one in 26.

This was not that alarming, said Dr Bunker - "we've all got to die of something".

Women were more likely to die of heart disease, he said, but less likely to be aware of that fact.

He said: "Breast cancer is not a trivial condition, we're all concerned about that. But most of it happens in the later years of life."

Dr Bunker said one particularly useful area of comparison was lung cancer.

Other diseases

The doctors reported that a woman smoker aged 50 was as likely to develop breast cancer as she was lung cancer.

However, by the age of 65 they were twice as likely to develop lung cancer and three times as likely by age 75.

"It's a question of perspective," said Dr Bunker.

Professor McVie agreed that fewer women were concerned about other areas of their health as a result, and were, for example, less likely to give up smoking.

"In Scotland and the North of England more young women die of lung cancer than of breast cancer," he said.