Hormone presents cancer risk

Post-menopausal women with high levels of the female hormone oestradiol in their blood are at higher risk of developing breast cancer, researchers have found.

A study of 2,500 women from Guernsey who were followed for 13 years from 1977 to 1990 found those with high levels of the hormone were up to five times more likely to develop breast cancer than those with low levels.

Blood samples taken from the women revealed the higher level of the hormone an average of eight years before the cancer was diagnosed, showing that it was not an effect of the disease.

The findings, published in the British Journal of Cancer, will improve understanding of the disease but do not offer a preventive technique. Screening for the hormone is not possible and the only known factor affecting its level in the blood is obesity, the scientists from the Imperial Cancer Research Fund say.