Thirty per cent of breast cancer 'is caused by obesity'

Thirty per cent of breast cancer 'is caused by obesity'

By Jenny Hope
Last updated at 8:09 AM on 26th March 2010

Up to a third of breast cancer cases could be avoided if women ate less and exercised more, researchers claim.

Experts believe more than 14,000 women a year would probably not develop the disease if they had adopted healthier behaviour from an early age.

Modern lifestyles which feature regular drinking, lack of exercise and increased obesity are fuelling the rise of the disease, the European Breast Cancer Conference heard yesterday.

Around 45,000 cases of breast cancer are diagnosed each year in Britain.

Carlo La Vecchia, of Milan University, told the conference in Barcelona: 'What can be achieved with screening has been achieved. It's time to move on to other things.'

Dr La Vecchia said the International Agency for Research on Cancer estimates that 25 to 30 per cent of cases could be avoided if women were thinner and did more exercise.

But Robert Baan, an IARC expert, said it was not clear if already overweight women could lower their cancer risk by slimming down or if long-term damage had already been done.

Around one in five British women is classified as obese. Research shows they are almost 50 per cent more likely to die from breast cancer than women carrying fewer pounds.

It is unclear why obese women are more at risk, although changes in sex hormone levels triggered by weight gain could be behind oestrogen-dependent tumours, which form the majority of cases.

The World Cancer Research Fund last year suggested up to 40 per cent of diagnosed women - around 18,000 a year - could avoid cancer by adopting a healthier lifestyle.

Studies show drinking one large glass of wine a day increases the chances of developing the disease by a fifth, say experts. Again, this could be linked to alcohol raising levels of oestrogen.

Dr Rachel Thompson said the WCRF had reviewed 954 separate studies.

'The evidence is now convincing that drinking alcohol, being physically inactive and having excess body fat all increase risk of breast cancer,' she said.

'There is also convincing evidence that breastfeeding reduces the mother's risk of breast cancer. Overall, we estimate about 40 per cent of breast cancer cases in the UK could be prevented through these lifestyle factors.'

Delegates also heard a warning from a British surgeon that increasing numbers of women who have a breast removed to treat cancer are panicking into having a second mastectomy.

Ajay Sahu, who works at Frenchay Hospital, Bristol, said many women diagnosed with the disease are extremely frightened and make the wrong decision in a hurry - despite little evidence it will improve their survival chances.

He said a study of 27 patients who had asked for the removal of their unaffected breast revealed all had overestimated their risk of developing a second tumour by five to ten times.

After 'cooling off' for a year, 23 chose not to have the second operation.

The conference will hear today how breast cancer survivors can safely try for a family without triggering a recurrence of the disease.

A review of 14 trials, involving thousands of survivors, showed that not only was pregnancy safe, it might improve their chances of beating the disease in the long-term.

Those who got pregnant had a 42 per cent cut in their risk of dying from cancer compared to those who did not have a baby, researchers found.

Read more: http://www.dailymail.co.uk/health/article-1260716/Thirty-cent-breast-cancer-caused-obesity.html#ixzz0jLB8Z2kr