Or, he is a jerk, and was trying to give you a hard time?
Well, if my gynecologist were to ask me that question, I would assume he wants to know a little bit more about the details? Like, perhaps you had a lumpectomy first that did not meet the margins? Or, maybe you had a huge fibroadenoma, or something benign as bb suggested? Or did you have advanced cancer, or stage one cancer, or ductal or lobular? I would hope a doctor who doesn't know any of my history, if this is the case, would want to know more than my telling him I had simply bc?
And if you have endometrial cancer than he really needs to know specifically about your need to be on estrogen antagonists, and/or possibly switching to an aromatase inhibitor?
Katrin
Are you saying that you don't know why you had your mastectomy??
If so, I would suggest that you arrange for copies of your records from your breast surgeon, and oncologist, if that is who is prescribing your tamoxifen, to be sent to your GYN. And at the same time, obtain copies for yourself, so you will be more knowledgeable about your own heath history.
If, on the other hand, you are just curious what the GYN meant about "many reasons to do mastectomy and give tamoxifen besides breast cancer," I would ask him/her what he/she meant, since it was his/her assertion...
The possible reasons, other than BC, I can think of' offhand, for a unilateral mastectomy would be a mutifocal precancerous condition, or a benign tumor involving a large portion of that breast, or chronic mastitis not responding to other treatment, but the latter two conditions wouldn't call for tamoxifen. Some people at high risk (BRCA 1 or 2 positive, for example) elect to go the route of prophylactic mastectomy, but that would be bilateral.
So ask the GYN to explain " the many reasons" he/she had in mind, and please let us know what answer you are given.
Best wishes...
If you did not have cancer and mastectomy was not done prophyllactically to remove breast tissue because you were at such a high risk then I guess I don't know why you would have had one done.
Tamoxifen is given to women who have cancers that are fed by estrogen. It blocks the estrogen from feeding the cancer.
Tamoxifen is a selective estrogen receptor modulator. Even though it is an antagonist in breast tissue it acts as partial agonist on the endometrium and has been linked to endometrial cancer in some women. Therefore endometrial changes, including cancer, are among tamoxifen's side effects. With time, risk of endometrial cancer may be doubled to quadrupled, which is a reason tamoxifen is typically only used for 5 years.
The American Cancer Society lists tamoxifen as a known carcinogen, stating that it increases the risk of some types of uterine cancer while lowering the risk of breast cancer recurrence. The ACS states that its use should not be avoided in cases where the risk of breast cancer recurrence without the drug is higher than the risk of developing uterine cancer with the drug.