Tuesday, June 17, 2008

Aromatase inhibitors and body aches

Many breast cancers behave enough like normal breast tissue that they are stimulated to grow in the presence of estrogen. While premenopausal women produce most of their circulating estrogen in their ovaries, the postmenopausal set converts androgens (male hormones) from their adrenal glands into estrogen via the aromatase enzyme.

For that reason, the risk of recurrence of estrogen receptor positive breast cancers can be reduced by either blocking cellular estrogen receptors with tamoxifen or preventing the production of estrogen with aromatase inhibitors. In fact, use of drugs such as exemestane (Aromasin) or letrozole (Femara) over 5 years has been shown to improve disease-free survival compared with 5 years of tamoxifen therapy.

Unfortunately, some women do not tolerate therapy with aromatase inhibitors due to joint pain. This discomfort may be due to the effects of lack of estrogen on tissues of the musculoskeletal system similar to the body aches experienced by some women as they enter menopause. Here's an excerpt from a March, 2008 issue of JAMA as one woman describes her experience with Aromasin:

As planned, I switched to taking exemestane [from tamoxifen]. But while taking it, I was feeling like I was a hundred years old. When I got up in the morning and opened my hands, all my joints would be sore and my arms hurt. All of my joints felt creaky. I started thinking, why should I stay on the exemestane for another 2 1/2 years? Why am I doing this to myself? So I called my doctor and asked him to switch me back to tamoxifen.

1 comment:

Haralee said...

You explained this very well.
As a breast cancer survivor who was on Arimidex, I went off because of the joint pain. At my support group we call it the Arimidex wave, curled up hand. When I mentioned to my oncologist the old woman shuffle he imitated it perfectly. The aromatase inhibitors have a better safety profile than tamoxifen, but there may be quality of life issues. Always choices and side effects!