Predictors of Adjuvant Endocrine Therapy in Women With Breast Cancer

Breast cancer is the leading cancer diagnosed in women and the second cause of cancer death. Of all racial/ethnic groups in the US, Black women have the highest rate of breast cancer deaths. Two-thirds of Black breast cancer patients have estrogen receptor (ER) positive tumors that can be treated with adjuvant hormonal therapy. If taken for the full five years, this therapy has been shown to reduce mortality by 50%. However, ER positive Black women are more likely to die from their breast cancer as ER positive White women. Preliminary data suggest that non-adherence to adjuvant hormonal therapy could explain some of this disparity. To date, no study has systematically examined psychosocial, healthcare, and biological factors that predict adherence to hormonal therapy in Black women with breast cancer. To begin to fill this knowledge gap, Investigators will conduct a prospective cohort study of 422 ER positive Black breast cancer patients recruited from health maintenance organizations (HMOs). Our primary outcome is adherence to therapy at 36 months post initiation. Specific aims are to: 1) Examine psychosocial factors (e.g. health beliefs, socio-cultural values, etc.) that predict adherence to hormonal therapy; 2) Identify clinical (e.g., side effects), and biological (e.g., stage, etc.) factors that predict adherence to hormonal therapy; and 3) Evaluate healthcare variables (e.g., communication, management of side effects, etc.) that predict adherence. Investigators will also explore the role of CYP2D6 genetic variations in adherence to hormonal therapy which is novel and will increase knowledge about this genetic factor in Blacks. The study is focused on the time-period (first 3 years) when women appear to be the most vulnerable to terminating treatment prematurely. A better understanding of predictors of adherence in Black women may help target interventions and ultimately improve potentially avoidable adverse breast cancer outcomes in this underserved group.