Over the past 30 years, the distribution of breast cancer stages at diagnosis in the U.S. has changed. The diagnosis of ductal in situ carcinoma (DCIS), or stage 0, and very early stage breast cancer (stage I) has increased. The diagnosis of stage II, III and IV breast cancer has either dropped or stayed about the same (see Figure 4.9).
Most recent Surveillance, Epidemiology, and End Results (SEER) data for U.S. breast cancer rates reported by stage. Source: Ries et al. .
Diagnosis of DCIS has increased by more than 350 percent in white women over 50 and by more than 400 percent in African American women over age 50 (see Figure 4.10). Large increases have been seen in diagnosis of DCIS and stage I breast cancer in women under age 50 as well . These changes suggest higher screening rates and better screening tools allow more breast cancer cases to be caught at early stages .
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Most SEER data for U.S. breast cancer rates reported by stage. Source: Ries et al. .
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 more likely to be diagnosed with early stage breast cancer than African American women [105-111].
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) [105-111].
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Most recent SEER data for U.S. breast cancer rates reported by stage. Source: Ries et al. .
Differences in stage at diagnosis make up a large part of the racial difference in breast cancer survival . When breast cancer is diagnosed at more advanced stages, chances for survival are lower (learn more).
Women who lack health insurance or access to good care and women with low income tend to be diagnosed with more advanced stage breast cancers than other women [105-107]. These factors may help explain, in part, racial differences in the stage at breast cancer diagnosis [105-107]. Efforts to improve breast cancer screening rates among women with low income and those who lack insurance, by addressing the barriers to screening, may help improve breast cancer survival [111,113].
There also appear to be differences in the biology of breast cancers that tend to occur in white and African American women. Studies show African American women are more likely to have breast cancers with factors linked to a poorer prognosis including [30,44]:
African American women (especially those who are premenopausal) also appear more likely than other women to have basal-like/triple negative breast cancer [30,44,48,50-54]. These tumors tend to have a poor prognosis compared to other subtypes of breast cancer. Triple negative breast cancers are:
Although the reasons for this are not clear, some lifestyle factors including breastfeeding and body weight might play a role [52,65,68-70].
Learn more about triple negative breast cancer.
Learn more about molecular subtypes of breast cancer.
Learn more about race, ethnicity and breast cancer risk.
Learn more about race, ethnicity and breast cancer screening.
Biologic differences may explain part of the racial differences in survival rates. However, later stage at diagnosis among African American women remains a major factor in these differences. Disparities in breast cancer diagnosis, care and survival are under active study.
Chances for Survival Based on Breast Cancer Stage