Study: Older Women With High Sex Hormone Levels at Twice the Risk of Breast Cancer

Postmenopausal women with high levels of estrogen and testosterone are at twice the risk of developing breast cancer as women with low levels of the hormones, according to researchers at Fox Chase Cancer Center.

A total of 663 women who had donated blood and later developed breast cancer were followed for an average of two to 12 years. Researchers compared nine hormones in their blood with the hormones of 1,765 women of the same age who were cancer free. The hormones studied included several forms of estrogen, androstenedione, dehydroepiandrosterone sulfate and testosterone, according to the study published in the Journal of the National Cancer Institute.

"The overall results show that postmenopausal women with higher serum sex hormone levels including estradiol and testosterone were twice as likely to develop breast cancer," said Dr. Joanne F. Dorgan, lead researcher.

"Associations between serum sex hormone levels and risk of developing breast cancer were not different in women who donated blood closer in time to diagnosis, indicating higher hormone levels in these women were not a preclinical finding," added Dorgan.

"The results are highly statistically significant and were not altered when we adjusted for established risk factors for breast cancer," said Dorgan.

Researchers are hopeful that their findings will help identify more women who are at a greater risk of developing breast cancer.

Other Sources: Journal of the National Cancer Institute, Fox Chase Cancer Center