Hi, Tina. I was diagnosed last year with Stage1A, Invasive Ductal Carcinoma, ER+ and HER2+++. Following surgery and three months of Taxol and Herceptin infusions, I was a wreck. Being age 70 probably didn't help. I then chose to discontinue the 9 additional months of Herceptin, and not have radiation. The last recommended treatment was Arimidex (anastrozole). I assessed all the damage from the chemo and targeted immune therapy and decided that i would take half a dose each day and see what the side effects might be. (If, for example, my next bone density test — in about a year — shows significant loss, then I will re-evaluate taking Arimidex for an additional five years or so. If I have a recurrence of breast cancer, then I likely will opt for mastectomy and a full dose of Arimidex, etc.) It's been difficult to tell whether it has made my neuropathy and chemo brain worse or whether they would be this way in any event, but I definitely am experiencing increased arthralgia, and bouts of toe cramps and depression (which is unlike me). As my hair still is growing out following the chemo, it's hard to tell if the Arimidex is messing with that or not. I seem to react negatively to even small doses of medications, so each suggested med. can be a problem.
My oncologist indicated that, if I had trouble with Arimidex, there were others which I could try. If you go to breastcancer.org, you'll find a Hormonal Therapy Side Effects Comparison Chart for seven different aromatase inhibitors (displayed side-by-side). As you can see, none are without potential side effects; not all patients experience the noted side effects; and other side effects can't be ruled out. (You'll note that hair-thinning is not specifically associated with Arimidex.) The trade-off for me is whether the side effects from any AI are preferable to the risks of awakening one day with metastatic cancer.