Risk Model May Accurately Predict Aromatase Inhibitor Nonadherence

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A novel risk model may be effective at using baseline sociodemographic and financial measures to predict the risk of long-term aromatase inhibitor nonadherence among patients with breast cancer, according to new findings presented by Hershman et al at the 2023 San Antonio Breast Cancer Symposium (Abstract PS04-08).


About two-thirds of the patients who receive treatment for breast cancer have hormone receptor–positive disease and are often prescribed aromatase inhibitors to reduce hormone production. 

Previous studies have shown that receiving aromatase inhibitors daily for several years can significantly reduce the risk of breast cancer recurrence. However, because of the common side effects of treatment, such as bone pain and hot flashes, many patients stop taking aromatase inhibitors early.

“We recognize that nonadherence to endocrine therapy is multifactorial. Predicting who is at risk will help us target personalized interventions to the right patients,” explained lead study author Dawn L. Hershman, MD, MS, the American Cancer Society Professor of Medicine and Epidemiology at the Columbia University Irving Medical Center, Deputy Director of the Herbert Irving Comprehensive Cancer Center, and Group Co-Chair Elect of the SWOG Cancer Research Network.

Study Methods and Results

In the new study, researchers analyzed data—including measures of patient adherence to aromatase inhibitor therapy for hormone-sensitive breast cancer—from over 700 postmenopausal patients who participated in the SWOG S1105 clinical trial. All of the patients had been prescribed aromatase inhibitors and were assessed every 3 months for continued use of the therapy.

The researchers then developed a novel risk model composed of individual sociodemographic, financial, area-level deprivation, and rural and urban location factors that demonstrated a correlation with aromatase inhibitor adherence.

They found that four of the factors had statistically significant associations with increased nonadherence to aromatase inhibitor therapy: younger age, a lower level of education, lower out-of-pocket costs, and residence in urban areas. Race and ethnicity were not found to be linked to nonadherence.

Further, the researchers discovered that the presence of each additional risk factor increased the risk of nonadherence by 47%. The patients who had more than two risk factors had a 64% greater likelihood of aromatase inhibitor nonadherence.


“These findings provide further evidence that a [patient’s] social and economic background can contribute vital information in predicting the course of their treatment,” emphasized senior study author Joseph Unger, PhD, Associate Professor at the Fred Hutchinson Cancer Center and a biostatistician and health services researcher at the SWOG Cancer Research Network. “This recognition is important for establishing early on which patients are at much greater risk of nonadherence to long-term [aromatase inhibitor] therapy, which could allow more effective targeting of interventions,” he concluded.

The researchers underscored that such interventions, in addition to symptom relief, should focus on structural barriers in high-risk patients.

Disclosure: The research in this study was was funded by the National Institutes of Health and National Cancer Institute and in part by the Conquer Cancer Foundation and the Breast Cancer Research Foundation.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.