DR LOVE: One of the issues, of course, out on the table now is duration of therapy and, in fact, extending out from years 5 to 10.

First, I’d like you to comment on the data very briefly that was presented at ASCO looking at this question, the big plenary presentation on extended AI therapy and how, if at all, it affected your clinical practice.

DR DICKLER: Right. So the much-awaited MA17 arm was presented by Paul Goss at ASCO. And it did show that continuing an AI, letrozole, after completing 5 years of an AI was beneficial in that it improved disease-free survival. However, the risk of distant disease-free survival was relatively low. And so, therefore, the incremental benefit in reducing the risk of distant metastases was small. And, really, much of the benefit was noted in reducing new primary cancers, both in the treated breast and in the contralateral breast.

So I think it’s interesting. We know that women have a risk of developing new cancers. And some of the benefit, much of the benefit, at least in the MA17R, was for chemoprevention. And also, many of those patients had had 4 to 6 years of tamoxifen. So in the majority of patients, it was really testing 15 versus 10 years of endocrine therapy. And I think that that’s something to remember. And it’s also a group of patients that, at least at that 5- to 10-year mark, were disease-free. So they’d already declared themselves as having indolent and/or endocrine-sensitive disease, right?

So I think that the data was also impacted by another presentation at ASCO, which was a look at the early breast cancer clinical trialists’ meta-analysis, where they analyzed the outcome of women who had completed 5 years of tamoxifen but no additional treatment. So 0 to 5, they had tam and then they were observed. And it’s individual patient data that’s reported back.

And I think it’s one of the strongest meta-analyses that we have. And they showed that even for a T1N0 ER-positive cancer, that at 20 years — so that’s 15 years of no endocrine therapy — I think about 21% of patients would have had an event. I think 7% of those would have been new cancers, but still, that there’s an event rate that happens year 5 through 20 that’s really more than what we really saw in MA17R.

So MA17R was a group of women that ultimately had a low event rate and an excellent outcome. But when you look at a more general population of patients that only had tam for 5 years, there’s definitely more events. And, therefore, the MA17R data means more to me than just the population of patients that was treated in that study.

Early-stage breast cancer (BC) in the adjuvant and neoadjuvant settings

Genomic assays and (neo)adjuvant treatment decision-making

Management of metastatic BC (mBC)

CDK4/6 inhibitors for the treatment of BC

Novel approaches under investigation in BC