Early Menarche May Play a Role in Development of Aggressive Breast Cancer in African American Women
Early age at menarche could play a role in the disproportionate incidence of estrogen receptor–negative breast cancers diagnosed among African American women, according to a study published in the Journal of the National Cancer Institute.
The study is a result of a multicenter collaborative research effort that formed the African American Breast Cancer Epidemiology and Risk Consortium (AMBER), which includes Christine Ambrosone, PhD, Professor and Chair of the Department of Cancer Prevention and Control at Roswell Park Cancer Institute (RPCI); Andrew Olshan, PhD, Professor and Associate Director for Population Sciences at the University of North Carolina Lineberger Comprehensive Cancer Center; and Julie Palmer, ScD, Professor of Epidemiology at the Slone Epidemiology Center at Boston University.
AMBER researchers investigated the epidemiologic and genetic causes for more aggressive breast cancer in African American women. They combined four epidemiologic studies with large numbers of African American participants: The Black Women’s Health Study (BWHS), the Multiethnic Cohort Study (MEC), the Carolina Breast Cancer Study (CBCS), and the Women’s Circle of Health Study (WCHS).
The goal was to examine whether relationships between age at menarche and breast cancer are the same for tumors that are estrogen receptor–positive or estrogen receptor–negative, particularly among African American women.
Analysis Findings
Analysis of data from 4,426 African American women diagnosed with breast cancer and more than 17,000 women without the disease showed that the pathways to estrogen receptor–negative and estrogen receptor–positive breast cancer appear to be different.
“It is known that exposures such as ionizing radiation have a great impact on the risk of women who are later diagnosed with breast cancer if the exposure occurs during puberty, a time when breast cells appear to be extremely sensitive. Indications are that the resulting cancers tend to be estrogen receptor–negative. African American girls tend to have earlier menarche than European Americans, and that age is getting younger over time. It is possible that early age at menarche could play a role in the disproportionate number of estrogen receptor–negative breast cancers diagnosed in African American women,” said Dr. Ambrosone, lead author of the study.
Reduced risk of estrogen receptor–positive breast cancer with later age at menarche was primarily observed among women who had previously had children, with the greatest increased risk for those with longer spans between menarche and childbirth. However, for estrogen receptor–negative breast cancer, childbirth status had no impact on the protective effects of later age at menarche.
The researchers concluded that age at menarche may be critical, even in the development of estrogen receptor–negative breast cancer, regardless of having children, and that the origins of estrogen receptor–negative vs –positive breast cancer at the cellular and molecular levels may be different.
“These analyses are from the largest study of breast cancer in African American women, to date. The AMBER Consortium used rich epidemiological data and information about breast cancer subgroups and included women from across the United States. We believe the findings from the study are generalizable to most African American women,” said Dr. Palmer, coauthor of the study.
“Our findings add further evidence to the growing knowledge that there are distinct etiologic pathways for estrogen receptor–negative and estrogen receptor–positive breast cancer. This study underscores that these differences likely begin at a very early age,” added Dr. Olshan.
This work was supported by the National Cancer Institute and the University Cancer Research Fund of North Carolina.
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