Epidemiology of breast cancer in young women

Breast cancer in young women is not a rare condition. Considering the US population, about 7 % of all cases are diagnosed before the age of 40, 2.4 % are diagnosed before age 35, and 1 % diagnosed before age 30. Breast cancer in young women has specific characteristics. In particular it has an aggressive course of clinical presentation, a higher rate of germline mutation in BRCA 1&2, distinct estrogen and progesterone receptor expression, and over-expression of human epidermal growth factor receptor 2. Further, they are partially different also in the epidemiological profile. In this chapter, we reviewed the epidemiology of breast cancer among women aged 40 years or less.