Early Menarche Linked to Aggressive Breast Cancer in African American Women.

Early age at menarche, or the first menstrual cycle, could play a role in the disproportionate incidence of estrogen receptor (ER)-negative breast cancers diagnosed among African American women, according to a study co-authored by a School of Public Health researcher.

The study, published in the Journal of the National Cancer Institute, is a result of a multicenter collaborative research effort that formed the African American Breast Cancer Epidemiology and Risk Consortium (AMBER). 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, the Multiethnic Cohort Study, the Carolina Breast Cancer Study, and the Women’s Circle of Health Study.

The goal was to examine whether relationships between age at menarche and breast cancer are the same for tumors that are ER-positive or ER-negative, particularly among African American women. ER-negative breast cancer is generally more aggressive and known to be associated with a poorer prognosis than ER-positive disease.

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 ER-negative and ER-positive breast cancer appear to be different. A reduced risk of ER-positive breast cancer with later age at menarche was primarily observed among women who previously had children, with the greatest increased risk for those with longer spans between menarche and childbirth. However, for ER-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 ER-negative breast cancer, regardless of having children, and that the origins of ER-negative versus ER-positive breast cancer at the cellular and molecular level may be different.

“These analyses are from the largest study of breast cancer in African American women to date,” said co-author Julie Palmer, professor of epidemiology at SPH and senior epidemiologist
 at BU’s Slone Epidemiology Center. “We believe the findings from the study are generalizable to most African American women.”

AMBER includes researchers from the Roswell Park Cancer Institute (RPCI), who led the study, and the University of North Carolina Lineberger Comprehensive Cancer Center.

The work was supported by the National Cancer Institute (NCI) and the University Cancer Research Fund of North Carolina.