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William J. Gradishar, MD, FACP, FASCO
William J. Gradishar, MD, FACP, FASCO
Posted: Tuesday, November 5, 2024
A recent cohort study of more than 17,000 women found that pregnancy-related factors may increase the incidence of breast cancer, especially for those already at a higher baseline risk. Jasmine A. McDonald, PhD, of Columbia University Irving Medical Center, New York, and colleagues analyzed such factors as parity, age at first full-term pregnancy, number of pregnancies, time since last pregnancy, and breastfeeding, focusing on the potential connection to breast cancer risk. These findings highlight the importance of considering individual breast cancer risk factors, including pregnancy-related ones, in developing more tailored screening and prevention guidelines for breast cancer, especially for women at higher risk.
“With 943 incident breast cancer cases identified among 17,274 women, this cohort study provides the first large-scale evaluation of pregnancy-related factors and breast cancer risk across a spectrum of risk based on absolute estimated risk of breast cancer that we know of,” the investigators commented. “This study suggests that pregnancy-related factors and breast cancer risk are modified by estimated absolute risk of breast cancer, with associations observed for estrogen receptor (ER)-negative disease. Women with a recent pregnancy and greater underlying breast cancer risk were at an elevated risk of developing ER-negative disease.”
In this cohort study, the mean patient age was 46.7 years; about 5% (n = 791) were Black, about 8% (n = 1,399) were Latinx, and approximately 80% (n = 13,790) were White. The study emphasized that breast cancer risk increases in women with higher pregnancy-associated risk scores, particularly after a recent pregnancy. Pregnancy-associated risk scores were evaluated using data from BOADICEA version 3, which hosts multigenerational data on breast and ovarian cancers in relatives, according to the authors. ER-negative breast cancer was also found to be associated with increasing years since last pregnancy and seemed to be more likely in women who had their first pregnancy after age 20.
Disclosure: For full disclosures of the study authors, visit jamanetwork.com.
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