Early stage diagnosis of breast cancer and survival after stage I diagnosis varied by race and ethnicity, and could be statistically accounted for by intrinsic biological differences, according to an observational study of 452,215 American women diagnosed with invasive breast cancer between 2004 and 2011.

The odds ratios for being diagnosed at stage 1 rather than a later stage, compared with non-Hispanic white women (OR, 1) are as follows:

• Japanese: 1.24

• Chinese: 0.97

• Other Asian: 0.80

• Other ethnicity: 0.75

• South Asian: 0.66

• Black: 0.56

Deaths from stage I breast cancer were highest among black and Hispanic women, and lowest among all Asian ethnicities included in the report. Biologic differences such as lymph node metastasis, distant metastasis, and triple-negative behavior of tumors may account for the statistical differences, the study authors suggest.

Citation: Iqbal J, Ginsburg O, Rochon PA, Sun P, Narod SA. Differences in breast cancer stage at diagnosis and cancer-specific survival by race and ethnicity in the United States. JAMA. 2015;313(2):165-173. doi: 10.1001/jama.2014.17322.