"I'm never going to put one of those pills in my mouth again," surgical oncologist Shayna Showalter, MD, recalls a patient telling her. As part of a clinical trial, the patient had tried hormone therapy for three months before undergoing surgery for her breast cancer.
In women 65 or older with early-stage, estrogen-receptor positive (ER+) breast cancer, standard treatment is surgery plus either radiation or hormone therapy. However, it can be difficult for patients to choose between radiation and hormone therapy when they don't know how they'll tolerate these options.
Researchers are evaluating whether trialing hormone therapy for 90 days before surgery (pre-ET) helps women choose a treatment they're more likely to stick with — thus, avoiding under- or over-treatment. The randomized, phase III study is called POWER II.
"While omitting radiation is often the right choice, it would be ideal to be able to individualize this decision, which would require knowing which patients were able to tolerate endocrine therapy," Showalter explains. "We know from the research we did with large national databases prior to writing POWER II that over-treatment is a significant issue nationally."
A Paradigm Shift in Breast Cancer Treatment for Older Women
Researchers expect the POWER II trial to show pre-ET helps patients better choose a treatment as it did in an earlier trial, POWER I.
"We hypothesize that there will be more patients being over-treated (surgery + radiation + endocrine therapy) and under-treated (surgery alone) in the standard of care arm when compared to the intervention arm," Showalter shares.
That result would likely prompt oncologists to begin including pre-ET in the standard of care.
"We believe the POWER II trial will result in a paradigm shift in the way that older women with breast cancer are treated," Showalter says. "This approach will facilitate individualized treatment planning and a decrease of both over- and under-treatment — allowing women to have good oncologic outcomes without the burden of extra treatments. All of the treatment options have risks and benefits and impact on quality of life, so it's important to find the correct balance."
Pre-ET Helps Women Make More Informed Care Decisions
The POWER II trial builds on the POWER I trial that showed pre-ET worked as a useful decision-making aid.
For the woman who swore to never take hormone therapy again, trying it for 90 days helped her make the right treatment decision for her. "She was extremely hesitant to have radiation, took pre-ET, and did not tolerate it," explains Showalter. "This then prompted her to accept radiation, which she got through without issues. Thus, she had surgery and radiation and is neither over- or under-treated. Without pre-ET she would not be in that position."
"Conversely, I had a patient who claimed she was sensitive to all medications and would not tolerate endocrine therapy," Showalter shares. "After the 90 days, she was tolerating it very well and made the informed decision to omit radiation."