One in eight women will develop breast cancer in their lifetime and the rate is rising, alarming figures show.
Scientists blame obesity, alcohol and the growing tendency to delay motherhood for record levels of the disease.
Up to 47,700 women are being diagnosed every year, equal to 130 a day. That is double the number 30 years ago.
Testing time: Almost 50,000 women are being diagnosed with breast cancer every year
Experts describe the figures as a ‘wake-up call’ and say thousands could avoid the disease if they drank less, maintained a healthy weight and took more exercise.
The rise has also been blamed on the fact that increasing numbers are delaying motherhood and consequently having fewer children. The figures show that there are now 124 cases per 100,000 women, twice as many as any other type of cancer.
Scientists believe some forms of breast cancer are triggered by the sex hormone oestrogen, which is linked to obesity, alcohol consumption, having fewer children and not breastfeeding.
They also blame hormone replacement therapy taken by millions every year to combat the symptoms of the menopause.
Figures from Cancer Research UK show that 47,700 women were diagnosed in 2008, compared to 42,400 in 1999 and just 24,120 in 1978.
Women are most at risk once they reach the menopause and 22,900 new cases – almost half – occur among those aged 50 to 69.
Doctors believe many tumours are caused by unhealthy lifestyles and are urging women to change their eating and drinking habits, particularly during the menopause.
Probable causes: Experts blame lifestyle choices such as alcohol and obesity, along with a growing wish to put off motherhood, for the spike in cancer rates
Research has found that obesity increases the risk of breast cancer after the menopause by up to 30 per cent. The overweight are also more likely to develop tumours.
Fat cells produce oestrogen and levels of this cancer-triggering hormone can be twice as high in obese women as those of a healthy weight.
Alcohol is also thought to raise the levels of oestrogen. Previous studies have shown that drinking even only one glass of wine a day can raise the risk of breast cancer by a fifth.
Women may also be increasing their risk by having fewer children, or none at all, because the levels of oestrogen decline during pregnancy. those who delay motherhood and consequently have fewer babies will be exposed to oestrogen for a higher proportion of their lives.
The risk is elevated further because breast-feeding has been shown to protect against the tumours as it lowers the level of oestrogen and other hormones.
Dr Kat Arney, from Cancer Research UK, said: ‘there are several lifestyle factors such as alcohol, weight and activity which increase the risk.
‘it is also linked to a woman’s reproductive history. If a woman starts having children earlier in life she is less at risk. A woman who does not start having children until her thirties will only have one, maybe two.’
She added that the popularity of HRT was also a factor and urged women to take it for as limited a time as possible.
Dr Rachel Greig, of Breakthrough Breast Cancer, said: ‘These figures are a wake-up call and should not be ignored.
‘more women are developing breast cancer and, although survival is improving thanks to breakthroughs in breast awareness, screening and treatment, we clearly have much further to go.
‘A two-pronged attack is needed – commitment to research into the causes of breast cancer, supported by women arming themselves with knowledge of the risks that may contribute to the disease.
‘Some risk factors, such as getting older, cannot be changed but the good news is that others can. by drinking less, maintaining a healthy weight and getting physically active, women can reduce their risk of developing breast cancer.’
A major study in 2009 said that more than 40 per cent of breast cancers could be prevented if women made simple lifestyle changes.
The report by the World Cancer Research Fund advised women to take least 30 minutes of exercise a day and limit alcohol to one unit a day – a single small glass of wine.