A new study has reported that African-American women experience a higher risk of additional breast cancer in the same breast compared to white American women after a diagnosis of ductal carcinoma in situ (DCIS). There is compelling evidence of differences in the biology and behavior of invasive breast cancer between African-American and white women.
The study included 100 African-American and 236 white women whole were diagnosed between 1990 and 1999 with their first primary DCIS. The women were identified using an institutional tumor registry. Method of diagnosis, treatment, and patient characteristics were obtained from electronic medical records. The average age was 60 for the African-American and 57 for the white women. The patients were followed using medical records until they received a diagnosis of a subsequent cancer or until their last day of contact with the institution. DCIS was typically found during routine screening mammography (81% of African Americans and 88.4% of white women). Tumor grade, margin status, necrosis, and type of treatment were not significantly different between the two groups.
African-American women were found to have almost four times the cumulative risk of additional breast cancer as white women during the first eight years, but this heightened risk was only for cancer in the same breast as the original DCIS. The authors conclude that, despite comparable clinical presentation and treatment, African-American women experienced a higher risk of second breast cancer in the same breast but not in the opposite breast. The observed excess risk of a second cancer in the ipsilateral breast is suggestive of intrinsic differences in the biology of cancer.