> Distribution of Breast Cancer Stages in the Population
Over the past 25 years, the distribution of stages of breast cancer has changed. The diagnosis of ductal in situ carcinoma (DCIS) and very early stage breast cancer (stage I) has increased. And, the diagnosis of stage II, III and IV breast cancer has either dropped or stayed about the same (see Figure 4.9). Diagnosis of DCIS alone has increased by more than 350 percent in white women over 50 and more than 400 percent in African American women over 50 (see Figure 4.10). Large increases have been seen in diagnosis of DCIS and stage I breast cancer in women under 50 as well. These changes suggest that higher screening rates and better screening tools allow more breast cancer cases to be caught in early stages when they are most treatable [38].
Race and breast cancer stages
Early stage cancers make up over half of breast cancer diagnoses in both white and African American women (see Figure 4.11). However, white women are much more likely to be diagnosed with early stage breast cancer than African American women [23,38-41]. Although racial differences in stage at diagnosis are decreasing, African American women are still more likely than white women to be diagnosed with cancer at advanced stages (stage III and IV) (see Figure 4.11) [23,38-41]. Such differences in stage at diagnosis make up a large part of the racial difference in breast cancer survival (for more on this, see the Breast Facts section). Because African American women tend to be diagnosed with more advanced cases when breast cancer is not as treatable, chances for survival are lower. Access to good care and a lack of health insurance make it more likely that women of some ethnic groups and those with low income will be diagnosed at more advanced stages [39-41]. Efforts to improve breast cancer screening rates among African American women, by addressing the barriers to screening, may help improve breast cancer survival.
There also appear to be differences in the biology of breast cancers that tend to occur in white and African American women. Some studies have found that breast cancers in African American women are more often high grade, lack hormone receptors and have more mutations in the gene p53 [21,42-44]. All these factors are linked to a poorer prognosis. African American women also appear more likely to have basal-like/triple negative breast cancer (estrogen receptor-negative, progesterone receptor-negative and HER2/neu-negative), a subtype of breast cancer with a poor prognosis [42-46]. These biologic differences may explain part of the racial disparity in survival rates. However, later stage at detection and diagnosis among African American women remains a major factor in survival rate disparities. The issue of racial differences in breast cancer is an active area of research.
Updated 10/27/09
