tamoxfin vs arimedex

I was told back in October, 2007 that I had a tumor in my right breast...I was stage 1 no lymph nodes involved..did a lumpectomy, and then for several weeks radiation therapy.....Then I was told to take tamoxfin for five years, however, last June, 2008, I had to do a biospy because I have a mass growing (believe to be the use of this tamoxfin) which luckily, found negative....however, it is still growing....now the Doctor's want me to switch to arimedex....This I really don't want to do.....My question, should they just remove this mass.....should it grow larger....and continue on my medicine which will be two years in November....I really don't want to change.....For one, tamoxfin helps out with bone disorder....I am small bone.....secondly, I have adjusted to take this pill every day.....Please advise....

Thanks,

[Cleveland Clinic]

Dear desmarae,   Both arimidex and tamoxifen work in different ways to decrease estrogen and the purpose of this is to treat or prevent estrogen responsive breast cancer.  Arimidex blocks the conversion of androgen hormones (mainly stored in the bodies fat tissue) to estrogen, and used in only women who are post-menopausal. Over the internet without ability to evaluate the test results, physical examination and to put it all into context we cannot advise you about what to do with this mass, or whether the switch to arimidex is the right route to go in your situation.  You may want to seek a second opinion from a medical oncologist who can review all of the information about your case.  This may help you feel more confident about the recommendations.