Early-Onset Breast Cancer Rates Surge in U.S. Women Under 40, Study Finds

New research highlights significant geographic disparities and rising incidence rates, with environmental and lifestyle factors under scrutiny.

Breast cancer rates in women under 40 have increased nationwide, with the Northeast showing the highest absolute rates and significant growth from 2001 to 2020.
The five states with the highest early-onset breast cancer incidence are Maryland, New York, New Jersey, Hawaii, and Connecticut, with rates 32% higher than the states with the lowest incidence.
Researchers suggest that genetic factors alone cannot explain the rise, emphasizing the need to investigate environmental exposures and lifestyle behaviors like alcohol consumption and physical inactivity.
Non-Hispanic Black women have the highest incidence of early-onset breast cancer, while Hispanic women have the lowest rates across all U.S. regions.
The findings aim to improve risk prediction models by incorporating geographic and demographic factors, supporting targeted prevention and intervention strategies.