Study: Racial Disparities in Outcome of Neoadjuvant Endocrine Therapy for HR-Positive Breast Cancer Patients

Black women are suggested to be diagnosed with stage 3 HR-positive breast cancer and receive longer neoadjuvant endocrine therapy more often than White women.

Black women who were diagnosed with a later stage of hormone receptor (HR)-positive breast cancer and treated with neoadjuvant endocrine therapy were more likely than White women to experience cancer, according to results presented at the 15th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved.

“Our findings suggest that neoadjuvant endocrine therapy alone may not be the best approach in Black women who present with more advanced tumors,” said Veronica Jones, MD, an assistant professor in the Department of Surgery, Division of Breast Surgery at City of Hope, in a press release.

More than 70% of breast cancer cases include tumors that express HR- mainly estrogen and progesterone. Most women with HR-positive breast cancer are treated with endocrine therapy, which targets HRs, before or after surgery (neoadjuvant and adjuvant). However, Black women are 4 times more likely to die from the cancer than White women.

Researchers set out to analyze the different outcomes of neoadjuvant endocrine therapy between Black and White women. Jones and the research team analyzed 3521 White women and 365 Black women from the National Cancer Database (NCDB). The cohort had stage 1, 2, or 3 HR-positive breast cancer, received neoadjuvant endocrine therapy, and had identifiable tumor stage, nodule status, and metastases.

Black women had a 1.5 greater likelihood of being diagnosed with stage 3 cancer than White women, and they were also 1.6 times more likely to have cancer in their lymph nodes.

Compared to White women, neoadjuvant endocrine therapy lasted an average of 2 weeks longer for Black women (median 128 days) as well. Further, they had a greater chance of receiving it for longer than 24 weeks.

Neoadjuvant endocrine therapy only eliminated or downsized tumors to in situ lesion in less than 1% of all patients, and Black women were 2.9 times more likely to have this outcome than White women. However, Black women were 2.6 times more likely to experience tumor upstaging than White women.

“While lower-stage cancers in Black women responded better to endocrine therapy compared to White women, higher-stage cancers in Black women did more poorly in response to endocrine therapy,” Jones said in the press release.

Jones further explained that tumor biology might impact treatment options, and her research team is now investigating breast cancer tumor mutations and gene expression differences among White and Black women.

One limitation of the study was the non-existence of estrogen and progestereone receptor positivity percentages available, which are associated with a woman’s response to endocrine therapy. Additionally, the NCDB did not have information on how clinicians determined the stage of the tumor or patient adherence to therapy.

The new discoveries could expand target therapies available to Black patients.

“This project is a critical step in unpacking the heterogeneity of hormone receptor tumor biology,” Jones said in the press release. “It brings into question how we can more effectively manage this disease to mitigate breast cancer racial disparities.”

Reference

American Association for Cancer Research. Neoadjuvant Endocrine Therapy May Elicit Differential Responses in Black vs. White Women with Breast Cancer. AACR website . September 16, 2022. Accessed September 16, 2022. https://www.aacr.org/about-the-aacr/newsroom/news-releases/neoadjuvant-endocrine-therapy-may-elicit-differential-responses-in-black-vs-white-women-with-breast-cancer/