Reassuring News About All Three Aromatase Inhibitors

Hester Hill Schnipper, LICSW, OSW-C Program Manager, Oncology Social Work

MAY 03, 2018

  Aromatase inhibitors are the standard of care for post-menopausal women with ER positive breast cancers. Some also receive chemotherapy, but virtually all receive one of three AIs. The choice of which medication to use seems to depend on a doctor's personal experiences with her patients and, sometimes, other medical issues for a particular patient. I have known a few women who started on one of the three, experienced unpleasant side effects (e.g. headaches or mild nausea) and were switched to a different one that was tolerated without any problems. If you have ER positive breast cancer, you are likely aware of the ongoing discussion re the optimal amount of time to continue on the drug. Initially it was two or three years, first, of tamoxifen and then two or three (to total 5) additional years of an AI. Then the standard of care changed to most women receiving five years of an AI; more recently, that practice has lengthened, and many women stay on the meds for seven or ten years or longer. That decision depends on a woman's individual situation and her doctor's preferences.

  The AIs are also used in the treatment of women with metastatic or Stage IV cancers. For them, the plan is each one sequentially. That is, she takes one AI until there is progression of cancer and then switches to the second and, when it stops being useful, switches to the third. There are also now several combinations of using one of the AIs along with a second drug for women with Stage IV breast cancers.

  For the first time, there has been a study comparing the efficacy of the three drugs, and it turns out that they are equally helpful. This is wonderful news and reduces or eliminates any concerns about which one is best. Here is the report from Medscape about the Italian study. I give you the start and a link to read more:

First Trial of Three Aromatase Inhibitors: Similar Efficacy, Safety
Kristin Jenkins

The first-ever direct comparison of three adjuvant aromatase inhibitors for the treatment of postmenopausal hormone receptor–positive early breast cancer shows no significant differences in clinical efficacy or safety, according to an Italian research team.

In the randomized, open-label phase 3 FATA-GIM3 trial of almost 3700 women, the 5-year disease-free survival for patients treated with anastrozole (Arimidex, Novartis), exemestane (Aromasin, Pfizer), or letrozole (Femara, Novartis) was 90.0%, 88.0% and 89.4%, respectively.

There were no unexpected serious adverse reactions or treatment-related deaths, say Francesco Perrone, MD, of the Istituto Nazionale per lo Studio e la Cura dei Tumori, in Naples, Italy, and colleagues. No differences were observed between patient subgroups, even though more than 50% of patients were overweight or obese.

The study was published online February 23 in the Lancet Oncology.

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