Joe Said:

Why is breast cancer more common in post menopausal women?

We Answered:

Yes the chances of getting breast cancer in post menopausal women are comparitivelyl more due to Estrogen Exposure.

The more estrogen a woman is exposed to over her lifetime, the greater her risk for breast cancer. This includes women who began menstruating at a younger age, and those who are recent or current users of estrogen-progesterone hormone replacement therapy. Obesity increases the risk for breast cancer in postmenopausal women, because estrogen is produced in fat tissue once the ovaries stop producing the hormone.

Because growth of breast tissue is highly sensitive to estrogens, the more estrogen a woman is exposed to over her lifetime, the higher her risk for breast cancer.

Duration of Estrogen Exposure. Early age at menarche (first menstrual period) or later age at menopause may slightly increase a womans risk for breast cancer.

Hormone Replacement Therapy. Many studies have reported a higher risk for breast cancer in postmenopausal women who take combination hormone replacement therapy (HRT), which contains both estrogen and progesterone. Combination HRT is used by women who have a uterus, because estrogen alone can increase the risk of uterine cancer. Estrogen-only hormone replacement therapy is prescribed for women who have had a hysterectomy.

Another reason is Obesity which increases the risk for all types of estrogen receptor-positive breast cancers. Women who gain weight after menopause are most at risk. (On a positive note, losing weight after menopause decreases breast cancer risk.) In postmenopausal women, estrogen is produced in fat tissue. High amounts of fatty tissue increase levels of estrogen in the body, leading to faster growth of estrogen-sensitive cancers.-

Georgia Said:

Do you think abortion is a causative factor in Breast cancer?

We Answered:

YES, It can be a part of the game, the following article will give you some clue:

Genetic Factors and Family History of Breast Cancer -- Some families appear to have a genetic tendency for breast cancer. Two variant genes have been found that appear to account for this: BRCA1 and BRCA2. The genes p53 and BARD1 also appear to be important. Researchers have identified some other defective genes that may cause breast cancer, including BRCA3 and Noey2 (which is a disease inherited only from the father's side of the family).

These facts suggest that breast cancer is caused by the growth of genetically damaged cells. Such genetic damage is known to gradually accumulate in the cells of the body over time. Women carrying mutated BRCA1 and/or BRCA2 genes have a "head start" in this process.

Hormonal influences are important because they encourage cell growth. High levels of hormones during a woman's reproductive years, especially when they are not interrupted by the hormonal changes of pregnancy, appear to increase the chances that genetically damaged cells will grow and cause cancer.
HENCE ONCE ANYONE IS PREGNANT IT DISTURBS THE ABOVE HORMONAL SYSTEM.

Hope answered your question.