Anyone know if tamoxifen is more harmful than aromatase inhibitors?

@vickee, I believe you're asking which hormone treatments that reduce the risk of breast cancer returning may have side effects.

Hormone therapy for breast cancer is a treatment for breast cancers that are sensitive to hormones. These drugs can also be used for people who are at high risk of breast cancer to improve the odds of staying cancer-free — an approach known as chemoprevention or preventive therapy.

Here are two articles from Mayo Clinic that list the different medications, including:
- Medicines that block hormones from attaching to cancer cells, such as tamoxifen, toremifene (Fareston), fulvestrant (Faslodex)
- Medicines that stop the body from making estrogen, such as anastrozole (Arimidex). exemestane (Aromasin), letrozole (Femara).
- Treatments to stop ovarian function in premenopausal women
- Combining targeted therapy with hormone therapies

Also listed are the risks or side effects of each of the medications. As with most medications, there may be side effects. Not all people experience side effects. Sometimes they can be manageable. But sometimes the side effects can affect quality of life negatively.

@vickee, which treatment options have been discussed for you?

I was told that aromatase inhibitors were slightly more effective. But tamoxifen does not cause the same bone loss as AI's. Once over menopause most of us do AI's. Some premenopausal women suppress the ovaries with meds and take AI's but most premenopausal folks do tamoxifen. That is what my doctors told me. Mayo has a great book on Breast Cancer that I purchased to get a good overview back when I was first dealing with decisions.

Thanks. But my question is a little different. I do not mean how to work for two kinds of medcines for premenopausal and menopausal women.
What I mean: both medicine may have effects, for example:
Tamoxifen make cause uterine cancer, anastrozole or letrozole may led to osteoporosis
That is just some examples , may be there are other effects.
Generally speaking, which kind of medcine is more harmful? that is my question?
Between Tamoxifen (block hormones binding acceptor) and anastrozole or letrozole (stop the body from making estrogen).
For manopause woman, they always has been changed into aromatase inhibitors, alought they can continue to use tamaxifen. THAT MEANS MORE HARMFUL.

@vickee that is hard to answer. It depends on age and what your preference is. It's like comparing apples and oranges. AI's are considered more effective so some women who are younger, suppress ovaries so they can take an AI.

Side effect lists are on drugs.com. Experiences vary. I was more interested in what was most effective and did an aromatase inhibitor despite already having osteoporosis. People on AI's usually do Reclast or Zometa to protect bones.

If you are post menopausal did your doctor want you on an AI?

It is your choice. But I tried to focus on the positive- stopping cancer- rather than the negative- possible harms. I am not aware of any harms I suffered on an AI other than bone loss. But others have pain. You can always try switching to another AI, switching manufacturers or ultimately switching to tamoxifen if an AI doesn't work for you.

thanks, it is helpful. I did not know AI's is more effective. Doctor won't give ai's for premanpause woman.

I am on Letrozole/Femara AI. for the past 2.5 years. For me, little to no side effects, except as windyshores said, Zometa was given to me in my 1st dose a few weeks ago. I had low osteopenia 2.5 years ago after my breast cancer. No side effects that I have noticed from that. I do want to say that i walk 5-6 miles each day and drink 1/2 my bodyweight in water or more daily. What other factors affect our side effects? I was reminded to add in weight bearing exercise. I was61 when i started the AI and a decade plus past menopause.
I feel very good.

If you want to (or your doctor recommends) to take an AI and you were diagnosed when you're premenopausal, then you can go into menopause to take the AI. Either have ovaries surgically removed or you can be in "chemical" menopause through either Lupron or Zoladex. Both are monthly (sometimes once every 3 months) injections that will force your body into menopause so that you can take the AI. In terms of which one is worse for side effects, thats a personal decision between you and your doctor because it depends on your age and any other health conditions you have, plus what's important to you in your quality of life decisions. Some women may be more comfortable taking the slightly higher chance of uterine cancer with tamoxifen while others arent. Some women can tolerate AIs and some cant. Regarding which one works better, that is a discussion to have with your doctor b/c it really depends on which type of BC you have, stage, your age, etc.