Abstract P4-14-09: The effect of socioeconomic status and race on breast cancer tumour biology and stage at diagnosis
Authors: Sharma Priya , Kraemer Dale F , Osian Sarah M , Smotherman Carmen , Vincent Mia , Samiian Laila 
Published: May 2015

Introduction: Mortality from breast cancer has declined over the last 2 decades. However, not all racial groups have benefited equally. African American women continue to die from breast cancer at higher rates than do white women. While racial disparities exist in breast cancer outcomes, they may largely be explained by socioeconomic factors. The effect of poverty on more aggressive breast cancer has not been well studied. We evaluated the association of race, insurance, and age on breast cancer stage and tumour biology within an urban inner city safety net hospital.

Methods: A retrospective review of a prospective breast cancer database was used to identify 535 women with stage 0 to IV breast cancer seen at UF Health Jacksonville from the period January 2009-March 2013. Age, race and insurance status at the time of diagnosis were used as covariates for defining disparities in stage at diagnosis and tumour biology. Tumour profile was defined as four groups: luminal A (ER+, PR+, HER-2 neg), luminal B (ER+, PR neg, HER-2 neg), HER-2/neu positive, and triple negative. Insurance categories were defined as Commercial, Medicare, Medicaid/Charity.

Results: There was equal racial distribution between African American (47.3%) and white women (47.5%) with 5.2 % other races. A relatively large number of patients had Medicaid/Charity coverage (37.1%), followed by Medicare at 32.7 %, and 30.3 % had commercial insurance. The mean age was 58.8 (SD=12.9). There was no significant association between race and stage at diagnosis within our patient population (p=0.869). However, women with Medicaid/Charity coverage were diagnosed at more advanced stage compared to women with other insurnace (adjusted p-value &lt;=0.011). Stage III disease for Medicaid/Charity was 23.1% vs 13.4% for commercial & 12.7% for Medicare coverage. Luminal A was the most prevalent tumour biology overall (58%), but triple negative tumours were more frequent in the black population (26.6%) vs white (13.1%) vs other races (17.9%). More aggressive tumour biology was found in black women compared to white women (adjusted p-value=.0007), and those with Medicaid/Charity coverage compared to other insurance (adjusted p-value &lt;.0001). For example, 28.1% of Medicaid/Charity patients had triple negative tumours vs 14.8% of commercial and 14.9% of Medicare population. Younger women were diagnosed at later stages (r=-0.196, p&lt;.0001) and had more severe tumour subtypes (r=0.235, p&lt;.0001).

Conclusion: UF Health Jacksonville encounters a uniquely equal racial distribution of women with breast cancer. Within our population, women with lower socioeconomic status based on insurance type present with more advanced stage at diagnosis independent of race. Black race and Medicaid/Charity coverage was significantly associated with more aggressive tumour biology. These results suggest that socioeconomic factors may have a significant influence on the breast cancer disease process and may contribute to racial disparities in breast cancer outcomes.

Citation Format: Priya Sharma, Dale F Kraemer, Sarah M Osian, Carmen Smotherman, Mia Vincent, Laila Samiian. The effect of socioeconomic status and race on breast cancer tumour biology and stage at diagnosis [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P4-14-09.