Michelle E. Melisko, MD
As research of early-stage estrogen receptor (ER)-positive breast cancer continues, experts are relying more on extended adjuvant hormonal therapy with aromatase inhibitors, but are concerned about patient quality of life (QoL) with such treatment.
“My passion is to really try to figure out how to make the side effects of these therapies more tolerable and how to help women be able to actually have reasonably good and normal QoL while they're taking these therapies, so that we can increase compliance,” said Michelle E. Melisko, MD.
In an interview during the 2017 OncLive®
State of the Science SummitTM
on Breast Cancer, Melisko, a clinical professor of medicine at the University of California, San Francisco (UCSF), discussed a variety of pivotal trials with adjuvant hormonal therapy and other developments in the treatment of patients with ER-positive breast cancer.
OncLive: Can you give an overview of your presentation?
I spoke about the value of extending adjuvant hormonal therapy beyond 5 years and reviewed the data from clinical trials looking at extending tamoxifen beyond 5 years, tamoxifen followed by aromatase inhibitors, and the most recent data looking at aromatase inhibitors for 5 years versus 10 years.
It's been a very confusing time over the past year, because there have been several large clinical trials that reported out within 6 months of each other that seem to have disparate results. One was a positive trial suggesting that we should continue hormonal therapy, mainly an aromatase inhibitor, beyond 5 years. The second suggested that we shouldn't. But when we take a deeper dive into data, we realize that the results of these trials are very similar, and it simply has to do with the differences in the outcomes or results—one was statistically significant in favor of extending [therapy] and the other was not.
It has to do with the definitions of the endpoints, the patient population, and what they defined as being a statistically significant outcome. I spoke about that and hopefully it resolved some controversies and help oncologists understand a practical approach that I take to discussing this with patients in making it a very individualized decision. I also spoke a little bit about neoadjuvant endocrine therapy in advance of surgery.
We can give some form of treatment before surgery to improve the chances of a patient having breast-conserving surgery, and we are also able to risk stratify to help us understand which patients are going to have good outcomes after surgery and which won’t. In some tumor types, primarily strongly ER-positive cancers, the rates of the cancer going away completely—what we call pathologic complete response (pCR)—is very low in strongly ER-positive cancers. Using chemotherapy might not be the optimal approach, so I spoke about some of the data comparing neoadjuvant endocrine therapy with neoadjuvant chemotherapy to help the community of oncologists understand what we at an academic center do to guide our treatment recommendations for women who have these large, but potentially more biologically indolent, cancers.
How has treatment changed over the past couple of years?
At the 2017 ASCO Annual Meeting, there was a presentation about the MA17R study. This was a follow-up of a very well-known trial where patients who originally received 5 years of tamoxifen were randomized to receive either placebo or an aromatase inhibitor.
More than 10 years ago, we found out that continuing with an aromatase inhibitor was beneficial. However, this trial looked at the MA17R component, the “R” being the extension of an aromatase inhibitor beyond those 5 years. There were some women in this trial who had received hormonal therapy for as long as 15 years, and they looked at the added benefit of continuing an aromatase inhibitor for 10 years compared with 5. That trial did meet a statistically significant endpoint of reducing recurrence and improving disease-free survival.
At that time, it was a practice-changing data point. I came home from that meeting telling patients who were coming in, after having taken 4.5 or 5 years of an aromatase inhibitor, to say we now have data that say that they should continue this for 10 years. Fast forward about 6 months to the NSABP B-42 trial, which had a similar design but [included] patients who perhaps had never taken an aromatase inhibitor. They started out taking tamoxifen, took an aromatase inhibitor for 5 years, and then they were randomized to continue it for another 5 years or just stop.