Purpose: Recent research, although inconsistent, indicates that socioeconomic status (SES) may be associated with hormone receptor (HR) status. This study aims to examine the association between SES and breast cancer HR status within and across racial/ethnic groups stratified by age at diagnosis and tumor stage.
Methods: The study subjects were 184,602 women with incident breast cancer diagnosed during 2004-2007 and identified from the National Cancer Institute's Surveillance, Epidemiology and End Results program. Log-binomial regression assessed the risk of having breast tumors that were (1) HR-negative versus HR-positive and (2) HR-unknown versus HR-known between women who, at the time of diagnosis, were residing in high or medium poverty areas compared to low poverty areas.
Results: High poverty areas tended to have a greater prevalence of HR-negative tumors compared to more affluent areas. Although not always significant, this was observed among non-Hispanic white and Hispanic women regardless of age-tumor stage category, and only among young, non-Hispanic black women and non-Hispanic Asian/Pacific Islander women with regional and distant stage. High poverty areas also tended to have a greater prevalence of HR-unknown tumors compared to more affluent areas. Furthermore, significant trends between HR status and poverty level varied by race/ethnicity, age, and tumor stage.
Conclusions: Poverty may be related to breast cancer negative and unknown HR status. These findings suggest the effects of non-genetic factors on biochemical features of breast cancer, as well as imply a clinical importance to improve HR measurement or recording for low socioeconomic breast cancer patients.