Women who have asymmetrical breasts are more likely to develop breast cancer, a study reveals today.

The findings published in the journal Breast Cancer Research were based on a study of mammograms of 504 women taken 27 years ago which found that the risk of developing cancer grew with each 100ml increase in asymmetry.

Researchers at the University of Liverpool studied the mammograms of 252 women who did not have breast cancer at the time but later developed the disease and compared them with the same number of mammograms of women who remained cancer-free.

The results show that women who went on to develop cancer had a higher breast volume asymmetry than women who did not.

Dr Diane Scutt, who carried out the study, said the research showed that breast asymmetry was a significant independent predictor of breast cancer. "If women are in a high-risk category and they are found to have breast volume asymmetry maybe this will alert people to monitor them more closely," Dr Scutt said.

However, she stressed that most women have asymmetrical breasts to some degree.

"Asymmetry for most women is relatively normal. These findings have to be seen in light of a woman's entire risk profile."