Hormone receptors in breast cancer: racial differences in distribution and survival

The purpose of this study was to describe hormone receptor status and analyze the effect of receptors on survival from breast cancer. Comparisons were made between African-American and Caucasian racial categories. Breast cancer data from 1990 through 1997 collected by the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) Program were analyzed. Subjects were 993 Caucasian men, 12,303 African-American women, and 141,045 Caucasian women. The number of African-American men was too small to analyze separately (n = 93). In addition to analysis of estrogen and progesterone receptor status by sex and race, tumor and patient characteristics included age, stage at time of diagnosis, and tumor histology. The proportion of Caucasian men with hormone receptor positive tumors remained relatively high and stable for all ages. In women, the proportion of hormone receptor positive tumors increased with age, with African-American women having the highest proportion of hormone receptor negative tumors. Caucasian men had highest proportions of hormone receptor positive tumors in all histology and stage groups, while African-American women had lowest proportions of hormone receptor positive tumors in all stage and histologic categories. Survival for African-American women was significantly worse for each hormone receptor category. In multivariate analyses, race was a significant independent predictor of survival, but sex was not. Although reasons for differences in hormone receptor status by sex and race are unknown, several hypotheses are discussed with respect to differences in tumor histopathology and risk factors.