Breast cancer is the second most common cause of death for women and is the most common cause of death for women aged 45 to 55. In 2009, it is estimated that 192,370 American women will be diagnosed with breast cancer and that 40,170 women will die from this disease. This number of deaths would be second only to lung cancer as related to cancer-caused mortality (Figs. 24-1 and 24-2) (1).
Annual age-adjusted cancer incidence rates among females for selected cancer types, United States, 1973 to 2005. Rates are age-adjusted for the 2005 US population. (Reproduced, with permission, from Jemal A, Siegel R, Ward E, et al. Cancer statistics, 2009. CA: A Cancer J Clin 2009 July;59: 225-249.)
Annual age-adjusted cancer death rates among females for selected cancer types, United States, 1930 to 2005. Rates are age-adjusted to the 2005 U.S. population. (Reproduced, with permission, from Jemal A, Siegel R, Ward E, et al. Cancer statistics, 2009. CA: A Cancer J Clin 2009 July;59:225-249.)
In the early 1980s, the rates of breast cancer diagnosis rose sharply, likely related to increased mammographic screening, since it was the incidence of stage I carcinomas that rose most sharply. Data from the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute demonstrate that while the incidence of breast cancer has been stable since the late 1980s, there has been an increase in the percentage of breast cancers that are hormone receptor–positive, which is contemplated to be due either to new ligand receptor assays versus an increased use of hormone replacement therapy by women (2,3).
Breast cancer incidence has long varied in different regions of the world. Incidence is highest in Northern Europe and North America and lowest in Asia and Africa. Data suggest that this variability is due not only to environmental factors but also to lifestyle. This is supported by the observation that breast cancer incidence is higher in second-generation Asian immigrants in the United States (4).
Breast cancer overall mortality rates had been stable for more than 50 years prior to 1989. However, in the 1990s there was a steady decrease in breast cancer deaths per year. Mortality rates declined by 1.4% per year from 1989 to 1995 and thereafter by 3.2% per year. This is thought to be due in part to increased use of mammography, resulting in earlier diagnosis, and the use of effective treatments. Mortality rates continue to be higher for African-American women. This is thought to be due in part to disparities in terms of ...