Epidemiology

Breast cancer is an important public health challenge accounting for one in four cancers diagnosed in women and almost one in seven cancer-related deaths in women globally. In 2020, 2.25 million incident breast cancers and 685,000 breast cancer-related deaths were recorded, and these estimates are projected to rise to 3 million incident cases and over a million deaths by 2040. Although historically considered a “disease of the west”, it should be noted that in 2018 roughly 50% of all incident cases and almost 70% of all breast cancer-related deaths occurred in less developed regions of the world. Therefore, breast cancer is a global health challenge with different social and environmental factors influencing breast cancer incidence and outcomes in different regions of the world. The current section will discuss key issues in breast cancer epidemiology.