couple of question on breast cancer

Hello,

I'd appreciate if you could answer couple of questions for me. I am somewhat confused on several things.

1. If the pre-menopausal woman of 33 who used to take Tamoxifen have her uterus and ovaries removed would she be taking Arimidex after the surgery since Tamoxifen only has an effect on the estrogen produced by the ovaries? Also, after this surgery how much is her changes increasing in getting the heart decease or heart attack?

2. It's been said a lot that the chances of a woman in getting the breast cancer are increasing after she reaches the menopause. So why then the women who were diagnosed with the breast cancer before the menopause having their ovaries removed to enter the menopause earlier. I understand that the estrogen has an effect on the breast tissues, but then shouldn't the postmenopausal woman be in a less risk of getting the breast cancer since her ovaries are producing less estrogen?

3. If the pre-menopausal woman was prescribed Tamoxifen due to her being  95% estrogen+/progesterone+, would it matter that she still has her menstrual periods?

Thank you!

[CCF-RN,MSN-JS]

Dear innakap, 1) Tamoxifen works to interfere with estrogen binding sites on certain tissues, mainly breast tissue.  So no matter where the estrogen is being produced from (ovaries, stored in other body tissues) the mechanism of action of tamoxifen continues to work.  There is an increased risk of heart disease as well as osteoporosis with surgical removal of ovaries, and corresponding decrease in estrogen levels.  Risks and benefits need to be weighed individually.  A persons risk of breast cancer recurrence, and other risks of heart disease, osteoporosis - family history, lifestyle.  Are there modifiable risks that can be altered such as diet, exercise, not smoking?

2) The actual reasons for why there is an increase in breast cancer as we age is not known for sure, there are many theories, some having to do with hormone levels, others to do with carcinogen exposure at certain times, etc.  When we talk about risk factors we are looking at common factors in a group of persons with a certain disease - these are not causes of disease.  Decreasing estrogen levels through hormone therapy in estrogen responsive tumors (ER+) is a method of treating breast cancer, or decreasing recurrence of breast cancer.

3) Not all women will go into menopause (stopping of menstrual periods) with taking tamoxifen.  The closer someone is to natural menopause the more likely tamoxifen may induce menopause.  The continuation of menstrual cycles doesn't mean the tamoxifen is not effective.  As mentioned the mechanism of action above, it blocks estrogen from binding sites on breast tissue it does not stop estrogen production.