The Epidemiology of Pregnancy-Related Breast Cancers: Are We Ready to Deliver?

The dual effect of pregnancy on breast cancer risk has long been recognized. The short-term increase in breast cancer after pregnancy, particularly cancers that are more aggressive, contrasts starkly with the longer-term decrease. It remains unclear how these opposing effects of pregnancy relate to molecular subtypes of breast cancer, which impacts translation. Several methodologic challenges remain related to the study and operationalization of key constructs, which remain complicated by the correlation between age at pregnancies, overall parity, and intervals between pregnancies and cancer diagnoses. In this issue of CEBP, Vohra and colleagues address some of these major gaps as well as present novel data on the breast tissue microenvironment. The increasing incidence of invasive breast cancer in women under age 50 years requires improved clinical translation and identification of higher risk women after pregnancy. Thus, it is crucial to address the gaps in our biological understanding of pregnancy-related breast cancers. See related article by Vohra et al., p. 561.