Breast Cancer :: Racial disparity in breast cancer outcome linked to aggressive tumors

Malignancies of the breast can be more aggressive and associated with poorer outcome in African-Americans than other races, according to a new study. Published in the December 1, 2006 issue of CANCER, a peer-reviewed journal of the American Cancer Society, the study reviewed patient data from two different clinical trial protocols – to control for healthcare access biases – and found that African-Americans have tumors with poorer prognostic cellular characteristics and more aggressive clinical presentations, pointing to the possibility that racially influenced tumor biology may contribute to observed racial disparities in breast cancer outcome.

Population-based studies have demonstrated significant differences in breast cancer survival rates based on race, particularly among African-Americans who are more likely to die of their disease than Caucasians. However, other races have been poorly studied. An often hypothesized explanation is socioeconomic differences that impact healthcare and access. Recent data suggest, however, that there may be differences in the tumors at the cellular level that may contribute to poor clinical presentations and outcomes.

Led by Wendy A. Woodward, M.D. of the University of Texas M. D. Anderson Cancer Center in Houston, researchers reviewed medical records and outcome data from 2,140 Caucasian, Hispanic and African-American breast cancer patients enrolled in clinical trials, controlling for differences in treatment that compromise other studies. Patients were either treated with chemotherapy before (neoadjuvant) or after (adjuvant) mastectomy.

The researchers found that in both treatment groups African-American race was independently associated with poor tumor and clinical characteristics and low survival rates compared to both Caucasian-Hispanic cohorts. For example, African-Americans presented with more advanced disease and were likely to have estrogen-receptor negative tumors. Analysis to control for other confounding factors confirmed that African-American race by itself was associated with lower survival in both treatment groups.

This study, conclude the authors, supports previous data “that African-American women more frequently had ER-negative disease and high-grade tumors and that African-American race was associated with a poorer survival rate.” This was confirmed in “two independent data sets of patients treated on prospective protocols.”


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