By Jonesa Rodriguez - June 19, 2023
In Black women, breast cancer is the leading cause of cancer death. In fact, 41% of Black women are more likely to die from breast cancer than white women despite a lower incidence of the disease, according to the American Cancer Society.
This is the same for Black women diagnosed with hormone receptor-positive, HER2 negative breast cancer. While the overall survival rate is favorable, Black women face a higher mortality rate.
This racial disparity has left researchers wanting to know why. Dr. Kimberley Lee, medical oncologist in Moffitt Cancer Center’s Department of Breast Oncology, is looking for answers in a new study. She recently presented results at the 2023 American Society of Clinical Oncology (ASCO) Annual Meeting.
Lee’s research looked at how well patients followed endocrine therapy and how it impacts racial disparities.
“I study racial disparities in breast cancer outcomes because I believe that race should not predicate one’s health outcomes,” Lee said. “Hormone receptor-positive breast cancer has targeted treatments, but these pills can be difficult to take because of side effects. This study aimed to examine whether racial differences in how women take these pills contribute to racial differences in survival after breast cancer.”
Endocrine therapy, known as hormone therapy or hormone-blocking medications, treats breast cancers expressing hormone receptors such as estrogen and progesterone. These types of cancer feed off of hormones in the body, so hormone therapy decreases the levels of these hormones, essentially starving the cancer of the food it needs.
After surgery, breast cancer patients are given the medication to reduce their risk of recurrence and are prescribed to take it for five to 10 years.
Using data from Medicare, Lee looked at women over 65 who were diagnosed between 2007–2016, had surgery and initiated endocrine therapy. She studied the number of days the patients had pills compared to the days they should’ve taken the medication. The information was used to calculate if the patient was adherent.
While the data showed racial disparities in endocrine therapy adherence and overall survival, they accounted for a small fraction of racial disparities in survival.
“We found that the proportion of survival differences impacted by the differences in adherence was relatively low at 4%,” Lee said. “What this means is that other factors contribute to the disparities.”
Lee says her next step for the study is to continue the exploration of biological and systemic mediators of racial inequities in breast cancer outcomes. Her research will continue as she furthers her investigation to include younger women.