High breast density has been linked to an increased risk of developing breast cancer, a study published in the journal Breast Cancer Research has found.
Breast density refers to the ratio of glandular tissue and collagen to fat found in breasts. A larger amount of collagen and glandular tissue compared to fat is measured as higher breast density. The study, Risk Determination and Prevention of Breast Cancer, found that approximately 700,000 women in the UK are unaware that they are at risk of developing breast cancer, due to gaps in risk estimation models. Current models are based on factors such as family history hormone levels. The study recommends updating these models to include breast density, to give precise risk estimation.
Professor Anthony Howell, director of research at Genesis Breast Cancer Prevention, said: 'With current breast cancer risk models, we know we can predict fairly accurately that 10 per cent of women in the population are at high or moderate risk of the disease. We also know that by using currently available drugs up to half of breast cancers can be prevented in these women. However, there is a major gap in how we identify women at high risk who could benefit from preventive therapy. Additionally, there is a gap in determining how much the risk assessment would be improved by adding additional information about other risk factors, such as breast density, and the results of gene tests.'
The cause of high breast density is unknown, but has been linked in previous studies to high calorie diets. Research by charity Breast Cancer Campaign has found that the incidence of tumours in areas of high breast density is 25 per cent more likely than in low density areas of the breast. A survey conducted of women aged over 45 by the charity, showed that 83 per cent of women thought that more information about high breast density should be available. The survey also found that 84 per cent of women would want advice on reducing their risk of developing breast cancer if they were found to have a high breast density.
Baroness Delyth Morgan, chief executive of Breast Cancer Campaign, says: 'The best weapon in overcoming breast cancer is the ability to stop the disease occurring in the first place. To do this, we need better ways to identify who is most at risk. The emerging evidence on risk factors such as breast density, which we now know is putting hundreds of thousands of women at risk of developing breast cancer, must be taken into consideration and more must be done.'