My oncologist told me a hysterectomy will prevent breast cancer since my tumor was estrogen fed, and the hysterctomy will take the estrogen away.
Well, not really. Perhaps your oncologist was being a little casual with that explanation. Removing the uterus (a hysterectomy) doesn't do anything to remove estrogen. Estrogen is produced in the ovaries and also in abdominal fat cells. A bilateral oophorectomy (BSO) will lower your estrogen levels quite a lot but not completely to zero, because your body will still be able to make some in abdominal fat cells. In fact, that's why menopausal women put on weight around the middle - the body adds extra fat in an effort to get the estrogen level back up to where it wants it to be.
Most women with a history of breast cancer take either Tamoxifen or an aromatase inhibitor like Arimidex after they complete their treatment (chemo or radiation or both); which one they take depends on their menopausal status. The two drugs work very differently, but both can lower the risk of a recurrence.
In women with working ovaries, Tamoxifen works by affecting how different tissues respond to the estrogen that's circulating through the body. In the breast, it prevents the estrogen from encouraging tissue growth, so it "opposes" estrogen. However, in the endometrium (lining of the uterus), it encourages tissue growth, so it acts "like" estrogen, magnifying its effect. This is why there is a much higher rate of endometrial cancer in women who have taken Tamoxifen and why so many of them do end up having hysterectomies.
Aromatase inhibitors like Arimidex work by blocking the action of the enzyme Aromatase, which facilitates the conversion of testosterone to estrogen. It is prescribed to women who are either naturally postmenopausal or who have had their ovaries removed. It greatly reduces the amount of estrogen in the body even in spite of the presence of abdominal fat cells who would love to be making it. The improvement in recurrence rates for women on Arimidex is slightly better than for those on Tamoxifen. However, Arimidex is not used in women with working ovaries such as yourself.
Perhaps your oncologist was assuming that you'd have your ovaries removed, and that would lower your estrogen level? Has he/she mentioned anything about taking Tamoxifen or Arimidex? Women whose cancers were estrogen receptor positive generally do benefit from taking one of those medications, while those whose cancers were estrogen receptor negative do not. Theoretically, if you want to lower your estrogen levels drastically, having the ovaries removed and taking Arimidex would be the most effective (imho) way to do that. It is not necessary to remove the uterus in that scenario. If you were to elect to take Tamoxifen instead of Arimidex, however, removing the uterus prophylactically makes a lot of sense.
There is a third drug that may be of interest to you, also. It's called Herceptin. If they tested your tumor and it was Her2 positive, Herceptin may be a viable treatment option for you.
Herceptin does not cause endometrial proliferation; in fact, it is sometimes prescribed as an adjuvant therapy for women who had endometrial cancer.
What type of birth control pills were you on? While estrogen does encourage the growth of ER+ breast cancer cells, it does not cause breast cancer. In addition, there is some evidence that women on estrogen tend to develop easier-to- treat forms of cancer and have higher survival rates than women who get breast cancer and were not on estrogen.
However, there has been demonstrated an increase in breast cancer rates in women who had used the combination HRT Prempro, which is a combination of estrogen (Premarin) plus the synthetic progestin called Provera. The results seem to indicate that Provera is associated with a higher incidence of breast cancer. Coincidentally - or maybe not so coincidentally - I used Provera for several years in the 1990s and have been diagnosed with breast cancer twice since my hysterectomy.
If you are planning to have your ovaries removed, has your DR discussed how you will deal with the symptoms of surgical menopause? I'm kind of surprised you are having cycles now because many types of chemo cause chemical menopause; it sounds like yours isn't doing that. Anyway, surgical menopause can be a little rough to deal with, which is why, despite the breast cancer diagnoses, I am still on HRT and plan to stay on it - just no Provera!
- also, I was unable to tolerate Tamoxifen because of the side effects. There's considerable variation from woman to woman in how the quality of life changes as a result of either Tamoxifen use or surgical menopause, and I guess I am just one of the "lucky" ones who gets hit very hard to the point that I can't function on a day to day basis. You may want to have a discussion with your DR about how you will be able to manage symptoms if they become unbearable, and also how you will maintain your bone density, which can be a huge issue in menopause.
It's a lot to think about, I know. I went through it in the opposite order - hysterectomy first for prolapse and then
the breast cancer. I don't envy you having to make this decision but am confident you will do your homework and make the one that's best for you.