Breast Cancer Risk
Reported August 27, 2008
(Ivanhoe Newswire) — Your age at menopause and your breastfeeding practices can influence your risk of developing certain types of breast cancer, according to a new study.
The study at the Fred Hutchinson Cancer Research Center in Seattle was done to better understand the specific risk factors for the subtypes of breast cancer, which are classified by expression of the estrogen receptor, the progesterone receptor and the HER2 receptor. The results suggest there are distinct and separate hormonal risk factors associated with different subtypes of the disease.
Researchers looked at data from breast cancer patients aged 55 to 79 whose cells had either the estrogen and progesterone receptors (called luminal cancers), the HER2 receptor or no expression of estrogen, progesterone or HER2 (triple negative cancer).
Results show reproductive risk factors varied significantly by breast cancer subtype. For example, having your first period at an early age was associated with the risk of HER2 but not with any other subtype. Breastfeeding for six months or longer was associated with a lower risk of luminal cancer as well as triple-negative cancer. Finally, going through menopause at a late age and taking estrogen plus progestin hormone therapy were both associated with an increased risk of luminal cancer. There were no differences in the subtypes as far as the risks associated with number of children or the age when a woman first gave birth.
The authors say more studies on the causes of breast cancer subtypes are needed to better understand the biology of the disease.
SOURCE: CANCER, published online August 25, 2008