Anastrozole vs Letrozole vs Tamoxifen

Posted by katielee @katielee, Jan 23, 2019

Over two years out from initial Stage1 diagnosis. Lumpectomy followed by radiation, then began taking anastrozole for about 6-7 months. Side effects, mostly bone pain that eventually moved to my feet, were horrible as my job requires a lot of walking. Doc recommended a stay in the meds for about two weeks. Felt like a new person! I’m currently on Letrozole which has been a better fit for me until the last few months. Hair thinning (also happened with anastrozole); HOT FLASHES, severe fatigue, bone pain mainly in my hips, and depression. Not sleeping well, but Dr. isn’t sure that’s Letrozole. He gave me the option of coming off Letrozole for 7-10 days to see if I noticed a difference. If I improve, I’ll next try Tamoxifen. I know everyone reacts diffently to these meds, but I’d certainly appreciate some feedback from you guys before I make another change. Thanks so much!

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Hi @katielee
I took tamoxifen after breast cancer and had a vaginal discharge as a side effect. I’m now scheduled to have a hysterectomy because the tamoxifen has caused my uterus to be precancerous. I’m BRCA positive so was having ovaries and Fallopian tubes removed anyway. Everyone has different side effects from all the cancer prevention meds. Best wishes to you and your decision about what to do next!

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I am wishing you you an easy process with what is ahead. You have the right attitude in saying one thing leads to another. Friends are helpful during the process. Some of the best I met during cancer treatment.

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I had a lumpectomy on August 10th. It was small tumor and margins were clear. I find out next week regarding radiation therapy. Also oncologist suggested I either taken Letrozole or Tamoxifen to keep reocurrence down 50%,
I have be doing research on both. I already have osteporosis of the spine and hip but am not currently taking bone density medication for that. It seems that the bone weakness is more prevelant with Letrozole.
I am very concerned about taking either because of the side effects.
Any comments or information would be appreciated.

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@mag73

I had a lumpectomy on August 10th. It was small tumor and margins were clear. I find out next week regarding radiation therapy. Also oncologist suggested I either taken Letrozole or Tamoxifen to keep reocurrence down 50%,
I have be doing research on both. I already have osteporosis of the spine and hip but am not currently taking bone density medication for that. It seems that the bone weakness is more prevelant with Letrozole.
I am very concerned about taking either because of the side effects.
Any comments or information would be appreciated.

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There are several threads dealing with the drugs that get prescribed for breast cancer that have more recent posts. A Moderator might move your query to one that may be more helpful. You can also search under the drugs' names using three magnifying glass icon in the upper right corner of this page.

I just wanted to mention the above to help you get recent answers. The two drugs you're being offered are very different. Since they both are used when a cancer is estrogen sensitive, I'm deducting that yours is. The goal of the drugs is to 'starve' estrogen-fueled cancer cells. Tamoxifen is known as a SERM and blocks the estrogen by making it unavailable to the cells' receptors. It is usually prescribed for pre-menopause women for various reasons.

Letrozole is an aromatase inhibitor and works by stopping the production of estrogen in the body, similar in a sense, to extreme menopause. Estrogen is a key player in bone renewal so that has to be a consideration if you already have osteoporosis and will likely require that you also take meds to help offset the effects of the estrogen loss.

Please do research these drugs and read others' experiences as they are both powerful drugs with differing possible side effects. But then cancer doesn't play fair and requires worthy opponents…

You can learn about both drugs, and alternative aromatase inhibitors and one alternative SERM or Mayo Connect and elsewhere to develop a list of questions you'll likely want to ask your oncologist. And maybe consult an endocrinologist about the osteoporosis as well. The more you learn, the better able you'll be to make the decisions going forward. So it's good that you've started the process.

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@mag73

I had a lumpectomy on August 10th. It was small tumor and margins were clear. I find out next week regarding radiation therapy. Also oncologist suggested I either taken Letrozole or Tamoxifen to keep reocurrence down 50%,
I have be doing research on both. I already have osteporosis of the spine and hip but am not currently taking bone density medication for that. It seems that the bone weakness is more prevelant with Letrozole.
I am very concerned about taking either because of the side effects.
Any comments or information would be appreciated.

Jump to this post

My oncologist switched me from exemestane to tamoxifan last year after a bone density scan indicated osteoporosis and osteopenia she believed was exacerbated or caused by exemestane. She informed me that tamoxifan is more "bone friendly" – and will not cause further weakening of the bones. Thus far, hip pain upon getting up in the morning and hair thinning [which was a side effect of anastrozole as well] are the only side effects I have noticed. Best of luck!

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