MA.17R Trial Data Effect on Treatment of ER+ Disease

Transcript:Hope S. Rugo, MD: I think MA.17R does impact the way we think about and treat women who have hormone receptor—positive breast cancer. First, extending adjuvant hormone therapy is not for everyone. That’s clear. The benefits for women at low continued risk for distant recurrence or at low continued risk for a contralateral breast cancer will be very small. And so, it’s not going to be worth it for those women. But, for women who have a high risk, a high, ongoing risk of distant recurrence in particular, those women will benefit from ongoing aromatase inhibitor therapy. If you see a woman who has stage III invasive cancer and is 5 years out from an AI, that’s a patient I would encourage to continue with aromatase inhibitor therapy. And, in patients who aren’t tolerating the aromatase inhibitor therapy well, we could switch to tamoxifen. We’re still going to reduce their risk based on the data we have already. So, I do think it changes our approach to longer-term therapy, but it also makes us think very hard about who’s an appropriate patient to treat or who isn’t.

Ruth O’Regan, MD: In terms of selecting patients for aromatase inhibitors, first of all, of course, you’ve got to make sure they’re postmenopausal because these drugs do not work in patients who have functioning ovaries. And, that can be trickier than it sounds. Because if you’ve given somebody chemotherapy, for example, you may think they’re postmenopausal, but, in fact, they’re not, and that certainly has been described. After that, I do tend to lean towards choosing an aromatase inhibitor over tamoxifen, particularly in patients that have higher-risk cancers, given the fact that the trials that were done did show a modest improvement in outcome with these aromatase inhibitors versus tamoxifen. But, I also am very cognizant of the toxicity profile, so I always check a bone density test before starting somebody on aromatase inhibitor. And, if they’ve got a lower-risk cancer and already have osteopenia or osteoporosis, in those patients, I may start with tamoxifen for a few years and then switch them to an aromatase inhibitor, and, particularly, if they’ve had a hysterectomy. In the clinic, they’re the kind of things that we talk about with patients, in general, in terms of deciding which of the agents to use.

Transcript Edited for Clarity