Rates for breast cancer characteristics by estrogen and progesterone receptor status in the major racial/ethnic groups

It has been reported that age-specific breast cancer rates vary by estrogen receptor and progesterone receptor status. We report breast cancer rates for age-at-diagnosis, stage-at-diagnosis, histological grade and type by estrogen (ER) and progesterone (PgR) receptor status in six major racial/ethnic groups. The average annual age-adjusted rates for breast cancers with estrogen receptor positive (ER⁺), ER^–, progesterone receptor positive (PgR⁺), PgR^–, ER⁺PgR⁺, ER⁺PgR^–, ER^–PgR⁺ and ER^–PgR^– are determined from 123,732 breast cancers with known ER status, diagnosed from 1992 to 1998 from 11 Surveillance, Epidemiology, and End Results (SEER) cancer registries. For each racial/ethnic group, their ER⁺ (ER⁺PgR⁺ and ER⁺PgR^–) age-specific rates increased with age (but at a slower pace after ages 50–54) while their ER^– (ER^– PgR⁺ and ER^–PgR^–) age-specific rates did not increase after ages 50–54. The rank orders of the rates among the racial/ethnic groups varied by ER/PgR status. The stage I rates were greater than the stage II rates for the ER/PgR groups except for ER^– and ER^–PgR^– cancers. The grade 2 (moderately differentiated) rates were greater than the grades 3 and 4 (poorly differentiated and undifferentiated cancers) rates for ER⁺ cancers, but not for ER^– cancers. These results suggest that although breast cancer is a disease with enormous heterogeneity, the multiple types of breast cancer can be separated into distinct subgroups by their ER status, and perhaps by their ER/PgR status, and their cancer characteristics may be important in understanding the multiple nature of breast cancer.