Amye J. Tevaarwerk, MD
Endocrine therapy remains an integral part of the treatment paradigm for patients with estrogen receptor (ER)–positive breast cancer; however, questions remain on which patients should continue their therapy beyond 5 years.
“The idea [is] that most patients with hormone receptor (HR)-positive breast cancer who are still on endocrine therapy at 5 years are going to merit some sort of discussion about whether they should continue or not, and it is okay to individualize that decision on the basis of the patient preferences, side effects, and symptom burden,” said Amye J. Tevaarwerk, MD.
“There are a precious few absolutes in that 5-year decision range so […] hopefully we will have additional tools coming up to clarify it for us.”
While experts say the decision should be a personalized one and varies from patient to patient, there are ongoing clinical trials that are further exploring the potential of endocrine therapy and how it bodes well with other efficacious agents in the landscape.
For example, the ongoing phase III PALLAS trial is looking at the combination of the CDK 4/6 inhibitor palbociclib (Ibrance) with standard adjuvant endocrine therapy versus adjuvant endocrine therapy alone for patients with HR-positive/HER2-negative disease (NCT02513394). Investigators will determine if the addition of palbociclib improves the outcomes associated with endocrine therapy with a primary endpoint of invasive disease-free survival.
Tevaarwerk, an associate professor of hematology and oncology at the University of Wisconsin, lectured on extending endocrine therapy in ER-positive breast cancer during the 2017 OncLive®
State of the Science Summit on Metastatic Breast Cancer. In an interview, she discussed how physicians decide on extending endocrine therapy beyond 5 years for patients with ER-positive breast cancer, the tools she hopes will soon become available to help clarify this decision, and the clinical research in this population she is eagerly awaiting.
OncLive: What did you cover in your presentation on ER-positive breast cancer?
In my talk, I focused on extended endocrine therapy and the current state of the art [approach], with regard to what we know currently and what we believe we should do after 5 years of endocrine therapy in patients with ER-positive breast cancer.
What are the questions currently being asked when a patient has reached 5 years of endocrine therapy?
How did we get to the prior gold standard, which was to do 5 years of endocrine therapy and what was it that drove that thinking? It is always very important to consider what that data said. The current data seem to suggest that there may be circumstances for higher-risk individuals where we want to go for 5 years more [with endocrine therapy] and extend it to 10 years. There are a number of open questions. What patients are at a high-enough risk? What drugs will you use if you go more than 5 years? Are there really any tools for helping you pick out the patients you should consider doing that for?
Are there any data that suggest what patients to pick for extended therapy?
The current clinical trial data that we have looking at that, unfortunately, is of data and work that were started a long time ago where we may have set things up a little differently versus if we were doing those studies now.