Racial Differences in Breast Cancer Survival in Iowa


Address correspondence and reprint requests to: Sue A. Joslyn, Ph.D., Division of Health Education, University of Northern Iowa, Cedar Falls, IA 50614–0241, U.S.A.


Abstract: The purpose of this study was to determine the effects of race on breast cancer survival, while controlling for the effects of patient age and stage at diagnosis. Subjects were 35,594 women diagnosed with primary breast cancer in Iowa from 1973 through early 1993. Data on subjects were provided from the State Health Registry of Iowa's Surveillance, Epidemiology, and End Result program, a population-based tumor registry. To determine if race was a significant predictor of survival, independent of patient age and stage at diagnosis, Cox's proportional hazards multiple regression analyses were used to estimate relative risk of death between races. Separate analyses were conducted for outcomes of breast cancer deaths and deaths from all cancers. Results of univariate analyses indicated African-American women had significantly poorer survival from breast cancer. However, after controlling for patient age and stage at diagnosis, race was not a significant independent predictor of survival. African-American women were 1.18 times as likely to die from breast cancer as Caucasian women (95% confidence interval: 0.94, 1.50). Results were similar for all cancer mortality. African-American women had poorer survival from breast cancer than Caucasian women, apparently due to breast cancer diagnosis at significantly younger ages and more advanced stage. These results indicate that public health measures aimed at earlier diagnosis in African-Americans might produce success in reducing racial differences in survival.