The number of women with breast cancer is rising, with one in eight now developing the disease, figures show.
Breast cancer rates in Britain have increased by 3.5 per cent over the last decade, with 47,700 women diagnosed in 2008 compared with 42,400 in 1999.
This has pushed up the lifetime risk of the disease from one in nine women to one in eight.
Experts have blamed lifestyle factors, including obesity and drinking alcohol, for fuelling the rise.
Women are also more likely to have children later in life, and fewer offspring, which influences the risk.
Having a family history of the disease also increases a woman's chance of developing the disease, which kills about 12,000 in the UK every year.
The latest data, from charity Cancer Research UK, is published on World Cancer Day.
It reveals the biggest rise in breast cancer rates has been among women aged 50 to 69.
Over the decade, cases rose by more than six per cent in this age group while rates among younger women (25 to 49) dropped slightly by 0.5 per cent.
In 2008, around 22,900 women aged 50 to 69 were diagnosed with breast cancer – 48 per cent of the total number of cases.
Some 15,700 cases (33 per cent) were in women over 70 and 9,100 cases (19 per cent) in those aged 25 to 49.
However, more women are surviving the disease, with almost two-thirds living more than 20 years beyond diagnosis.
More than three-quarters of women diagnosed with breast cancer survive for at least 10 years.
Women in England aged 50 and over are eligible for breast cancer screening every three years. By 2012, this will be extended to women aged 47 to 73.
Around 1.5 million women are screened in the UK every year.
Cancer Research UK's director of health information, Sara Hiom, said: "Women can't change their genes but small changes in everyday habits can help to reduce cancer risk.
"Cutting back on alcohol by keeping within Government recommended limits of no more than 14 units a week (a small drink a day) helps.
"Taking more exercise and eating a diet high in fibre but low in saturated fat can help maintain a healthy weight, which in turn reduces breast cancer risk.
"Women should also discuss hormone replacement therapy with their doctor as long-term use can raise breast cancer risk."
The charity is also urging eligible women to go for screening.
Ms Hiom said: "Mammograms will pick up breast cancers early on before they can be felt as a lump or spotted through other visible changes.
"We know that the earlier a cancer is detected the more successful treatment is likely to be so women can benefit by taking up invitations to breast screening."
Jane Maher, chief medical officer at Macmillan Cancer Support, said: "These figures confirm what Macmillan professionals are seeing on the ground, that breast cancer is continuing to increase.
"There is some good news in that earlier diagnosis and better treatments mean that more women are surviving their cancer.
"In fact, there are now almost 550,000 women living with a breast cancer diagnosis in the UK.
"Therefore it is vitally important that resources are better used to ensure women get the care and support they need to have a good quality of life after treatment."
Diet and exercise can cut risks
The scientific and medical adviser for the World Cancer Research Fund, Martin Wiseman, said: "The increase in breast cancer cases is mainly because women are living longer and because alcohol consumption and obesity rates are rising.
"We can help to reduce breast cancer risk and other cancers by promoting the important of a healthy weight, healthy diet and plenty of exercise."