The Impact of Psychosocial Variables On Breast Cancer Subtype and a Proposed, Multi-Level Intervention

Background and Purpose:  Although the overall incidence rate for breast cancer is approximately 10% lower among African-American women than white women, African-American women have a 37% higher death rate from the disease overall.  One insight into this disparity is the recent discovery of various subtypes of breast cancer.  The triple-negative subtype of breast cancer (TNBC) is more lethal and aggressive than other subtypes, and may contribute to the disproportionate breast cancer mortality of African-American women.  TNBC is classified as negative on three key breast biomarkers:  ER, PR, and Her2. Those diagnosed with TNBC are more likely to be younger African-American women (39%), compared to postmenopausal African-American women (14%) and non-African-American women (16%) of any age.  There is evidence that increased likelihood of aggressive tumors such as those that are triple-negative occur more frequently in women who have history of experiencing discrimination. African-American women may experience greater discrimination and different returns on their human capital investments, such that they are compensated less than white women for the same education and occupational status. The purpose of this study was to explore the relationship between discrimination and breast cancer subtype in a sample of African-American breast cancer survivors.  Our research question is: What is the relationship between experiences of discrimination and aggressive breast cancer subtypes among African American women?

Methods:  Participants were 189 African-American women living in the same 15 neighborhood areas of Chicago who were diagnosed with breast cancer between 2005 and 2009. Complete data on tumor biology were available for all participants.  Tumor tissue was collected at the time of biopsy or surgical resection of the tumor.  Data on women’s psychosocial functioning were collected in their homes or other sites four to six weeks after surgery in face-to-face interviews.  Using PASW® Statistics GradPack 18.0, we explored the association between a number of social variables including discrimination and the biological characteristics of breast cancer using a logistic regression model with TNBC status as the outcome variable. 

Results:  Discrimination was a significant predictor of the triple-negative model (LR=1.19, 95% CI 1.01 to 1.41 and p=0.04), such that as discrimination increased, so did the likelihood of having triple-negative breast cancer.

Conclusions and Implications:  Given the impact of discrimination throughout the life course, the investigators have proposed a neighborhood support coordinator (NSC) intervention.  The NSC is a novel model of care that aims to address African-American breast cancer disparities in two primary ways. First, rather than being clinic based, this intervention focuses on engaging the women in the neighborhood and community in which they live. This is imperative in that the contextual environment is the critical place where such change must occur.  Secondly, the NSC helps the women to navigate overlapping systems rather than limiting the scope to the health care system only.   Buffering the effects of discrimination using an intervention that address these issues on multiple levels is key to minimizing health disparities in breast cancer outcomes.