1 Breast cancer is the most frequent cancer in women worldwide
the incidence rate of breast cancer decreased between 1999 and 2005 (by 2% per year) and has remained stable from 2005 to 2009 121. In contrast, the incidence of metastatic breast cancer in women younger than age 40 has been increasing in the USA.
2 The increase in metastatic disease in young women was shown to be independent of race and ethnicity but was more pronounced in Hispanic white and African-American patients and in women with estrogen receptor (ER)-positive
3 At a young age, breast cancers have a more aggressive biological behavior and have been correlated with larger tumor sizes, less hormone positive tumors, higher grade tumors, more frequent metastases to lymph nodes