A. Breast Cancer
Breast cancer is the most commonly diagnosed cancer among African American women. In 2013, an estimated 27,060 new cases of breast cancer were expected to occur among African American women. Among younger women (under age 45), however, the mortality rate of breast cancer is higher in African Americans than in whites. The median age of diagnosis is 57 years for African American women, compared to 62 years for white women. Breast cancer incidence rates increased rapidly among African American women during the 1980s, largely due to increased detection as the use of mammography screening increased, then rates increased more gradually during the 1990s. In the most recent time period (2000-2009), breast cancer incidence rates increased slightly among African American women (0.7% per year) and decreased among white women (1.0% per year). The decrease in white women during this time period in part reflects the sharp decline between 2002 and 2003 that was related to a drop in use of menopausal hormones. A similar drop in incidence was not observed in African American women among whom menopausal hormone use is historically lower.
Breast cancers diagnosed in African American women are more likely to have factors associated with poor prognosis, such as high grade, advanced stage, and negative hormone (estrogen [ER] and progesterone [PR]) receptor status, than those diagnosed in white women. Furthermore, premenopausal African American women in particular appear to have a higher risk for triple-negative (ER negative, PR negative, and human epidermal growth factor receptor [HER] 2 negative) and basal-like breast cancers, which are distinct but overlapping aggressive subtypes of breast cancer that are associated with shorter survival. Studies have shown that certain reproductive patterns that are more common among African American women (including giving birth to more than one child, younger age at menarche, early age at first pregnancy), may be associated with increased risk of aggressive subtypes of breast cancer.
A woman’s best overall preventive health strategy is to reduce her known risk factors as much as possible by avoiding weight gain and obesity (for postmenopausal breast cancer), engaging in regular physical activity, and minimizing alcohol intake. Women should consider the increased risk of breast cancer associated with combined estrogen and progestin menopausal hormone therapy when evaluating treatment options for menopausal symptoms.
The 5-year relative survival rate for breast cancer diagnosed in 2002-2008 among African American women was 78%, compared to 90% among whites. This difference can be attributed to both later stage at detection and poorer stage-specific survival among African American women. Only about half (15%) of breast cancers diagnosed among African American women are diagnosed at a local stage, compared to 61% among white women. Within each stage, 5-year survival is also lower among African American women than whites overall (60% versus 69%).
Studies have documented unequal receipt of prompt, high-quality treatment for African American women compared to white women. There is also evidence that aggressive tumor characteristics are more common in African American that white women. Other studies suggest factors associated with socioeconomic status may influence the biologic behavior of breast cancer. Poverty likely influences disease pathology and genetic markers of disease through lifelong dietary and environmental exposures, physical activity, and reproductive behaviors.
Breast cancer is the second most common cause of cancer death among African American women, surpassed only by lung cancer. An estimated 27,060 new cases of breast cancer and 6,040 deaths from breast cancer are expected to occur among African American women in 2013. Breast cancer death rates among African American women increased from 1975-1992 and declined thereafter as a result of improvements in both early detection and treatment. Breast cancer death rates have declined more slowly in African American women (1.4% per year from 2000-2009) compared to white women (2.1% per year). During 2005-2009, the average annual breast cancer incidence rate in African American women was 118.1 cases per 100,000 women, 4% lower than in white women (123.2). However, the breast cancer death rate in African American women was 31.6% compared to 22.4% in White women. The higher breast cancer mortality rate among African American women compared to white women occurs despite a lower incidence rate. Factors that contribute to the higher death rates among African American women include differences in access to and utilization of early detection and treatment and differences in tumor characteristics; however it is believed that much of this disparity remains unexplained.