Studies consistently have indicated a link between later onset of menopause and increased breast cancer risk. Reports show that women who go through menopause after age 55 have twice the risk of breast cancer as women who experience menopause before age 45.
To understand why women who begin menopause later in life are at a slightly elevated risk of developing breast cancer, one must understand the role of estrogen. Estrogen alone does not cause cancer. The hormone, estrogen, is an essential part of a womanís physiology. However, estrogenís principal function is to speed the process of cell proliferation. Therefore, estrogen can increase the chance of a mutation occurring and/or encourage the growth of cancerous cells once they appear.
The more estrogen a woman is exposed to during her lifetime, the greater the opportunity for the hormone to promote the growth of a tumor. The reason why women who go through menopause later in life are at greater risk of developing breast cancer is because these women have had a longer lifetime exposure to estrogen.