By the way, doctor: Tamoxifen versus aromatase inhibitors

Q. I've had an ER-positive breast cancer tumor removed. Now I am getting ready for follow-up therapy. I've heard that the aromatase inhibitors are better than tamoxifen. What is your opinion?

A. Breast cancer is classified according to whether it has receptors for the female hormone estrogen. If the cancer has estrogen receptors — or, as cancer specialists say, it is estrogen-receptor (ER) positive — estrogen can stimulate the cells to grow and divide, resulting in more cancer. About two-thirds of all breast cancers are ER-positive. The good news is that ER-positive tumors tend to be less aggressive than those that are ER-negative, so the prognosis tends to be quite a bit better. Still, blunting the effects of estrogen is important for preventing recurrence.