Temporal trend of breast cancer burden among younger and older Brazilian women, 1990-2019.

Objective: To analyze the temporal trend of the burden of breast cancer in Brazilian women under 40 years of age compared to the age group over 40 years of age, between 1996 and 2019.

Methods: An ecological time trend study was conducted in Brazil between 1996 and 2019 using data from the Global Burden of Disease (GBD) study. The segmented regression method (Joinpoint Regression) was applied to analyze rates among women under and over 40 years of age.