Cancer Research UK discounts uneven breast cancer risk

In collaboration with the Press Association

Cancer Research UK has described the increased breast cancer risk among women with asymmetrical breasts as "small" when compared to other factors linked to the disease.

The charity was responding to research which claimed that breast cancer risk was slightly increased in the larger breast of women with one breast substantially larger than the other. The increase in risk became greater the bigger the difference in breast size.

"We know there is a tendency for the left breast to be very slightly larger than the right breast and many studies have reported a slightly larger proportion of breast cancers to occur in the left breast (around 51 per cent)," said professor Stephen Duffy of Cancer Research UK.

"This study confirms the first observation but not the second. It also finds that having one breast substantially larger than the other is associated with increased risk of breast cancer.

"But this increase in risk is small compared with other risk factors such as breast density. So it does not have immediate implications for prevention or screening," he added.

The research, carried out by the University of Liverpool and published in the journal Breast Cancer Research, compared the mammograms of 252 women with breast cancer against around the same number from healthy women.

The report claimed that asymmetry may play a role in cancer, although the researchers noted: "It is important to consider a woman's entire risk profile before assessing her breast cancer risk."

Breast cancer is the most common cancer among women in the UK, with 42,000 new cases diagnosed every year.