Breast carcinoma survival analysis for African American and white women in an equal-access health care system.

BACKGROUND: This retrospective review of breast carcinoma cases in the Department of Defense (DoD) Central Tumor Registry evaluated differences in survival patterns between African American and white women treated in U.S. military health care facilities. The study examined the effects of age, stage of cancer, tumor size, grade, lymph node involvement, waiting time between diagnosis and first treatment, marital status, military dependent status, alcohol usage, tobacco usage, and family history of cancer.
METHODS: Researchers reviewed the tumor registry records of 6577 women (5879 whites and 698 African Americans) diagnosed with breast carcinoma. The patients, ages 19-97 years, were diagnosed between 1975 and 1994. A hazard ratio (relative risk of mortality) model compared African American and white patients, adjusting for various combinations of covariates; impact of independent variables on the risk of death; prognostic factors significantly associated with survival; disease free and overall survival times; effects of ethnicity, stage, and age on survival; and trends in stage at diagnosis. A P value (2-sided) of less than 0.05 was considered statistically significant.
RESULTS: After adjustment for age, the risk of death was 1.45 (95% confidence interval [CI], 1.20-1.76) times greater for African American women than for white women. Adjustment for stage reduced the risk to 1.41 (95% CI, 1.16-1.70); further adjustment for demographic variables and most clinical variables had no effect. Still, African American women treated in the military health care facilities had a better survival rate than African American women represented in the Surveillance, Epidemiology, and End Results (SEER) Program of the National Cancer Institute. In our study, the 5-year risk of death, from any cause, was 1.37 for African American women with breast carcinoma; in other words, the mortality rate for African American women was 24.77% compared with 18.08% for white women. In the latest SEER data, the 5-year relative risk of death for African American women compared with white women is 1.86. The mortality rate in SEER is 34.2% for African American women and 18.4% for white women. The survival rate for white DoD beneficiaries is comparable to that for white women in SEER.
CONCLUSIONS: These observations suggest that ready access to medical facilities and the full complement of treatment options that are standard for all DoD patients improve survival rates for African American women. However, a significant unexplained difference in survival still exists between African American and white military beneficiaries.