Early stage interval breast cancers in African-American women demonstrate ER negative status and more aggressive tumor biology

Proc Amer Assoc Cancer Res, Volume 45, 2004 5259 It has been suggested that biologic factors may contribute to the limited efficacy of mammography and poorer breast cancer outcomes in African American (AA) women. To further investigate, we retrospectively evaluated tumor biology of interval cancers diagnosed in 254 consecutive AA women with breast cancer at the John Stroger Hospital of Cook County, Minority-Based Community Clinical Oncology Program, which serves the medically-indigent in Chicago. A total of 51 AA women were diagnosed with interval cancers; 30 had AJCC stage 0-1 and 21 had stage 2-4 cancers. For women with stage 0-1 cancers, interval cancers were significantly more likely to be hormone receptor (ER) negative (33% vs. 13% for non-interval cancers; Chi-square p<0.05). This difference was not apparent for stage 2-4 cancers (48% vs. 41%). Stage 0-1 interval cancers were less likely to be diploid (52% vs. 65% for non-interval cancers), more likely to have high tumor grade of differentiation (38% vs. 21%), more likely to be HER2/neu positive (30% vs. 19%), and more likely to be p53 positive (83%), although these differences were not significant. Stage 2-4 interval cancers were also more likely to be HER2/neu positive (43% vs. 33% for non-interval cancers), and none were found to be well differentiated. This study although limited by size, demonstrates that early stage interval breast cancers in AA women have more aggressive tumor biology, compared to non-interval screen-detected cancers. This finding may partly explain the limited efficacy of screening mammography in AA women and requires further study.