P2-14-08: Hormone Receptor Status and Breast Cancer Survival among Hispanic and Non-Hispanic White Women over 10 Years of Follow-Up.

Abstract

Introduction: The joint presence or absence of expression of estrogen receptor (ER+/−), progesterone receptor (PR+/−), and Her2neu (Her2+/−) is now widely used to define the hormone receptor (HR) phenotype of breast tumors. HR phenotype influences breast cancer etiology, response to treatment and survival, which may vary by ethnic group. The triple negative phenotype (TNT: ER-/PR-/Her2-) is associated with the poorest survival and is more common in African American than white women. Few studies have assessed how HR status differs by Hispanic (H) versus non-Hispanic white (NHW) ethnicity in relation to survival. Methods: We analyzed data from the New Mexico site of the ‘Health, Eating, Activity and Lifestyle’ (HEAL) study for breast cancer mortality over 10 years of follow-up by HR phenotype and ethnicity for 126 H and 408 NHW women with invasive (I-IIIA), first primary breast cancer. Kaplan Meier curves were used to describe differences in survival by ethnicity and HR phenotype (ER+/PR+/Her2+, referent; ER+/PR+/Her2-; ER-/PR-/Her2+; and ER-/PR-/Her2-). Hazard ratios were estimated using Cox regression models stratified by phenotype and ethnicity, adjusting for age at diagnosis, stage, and diagnosis of another cancer (yes/no). Results: Kaplan Meier (KM) analysis indicated that the TNT phenotype was associated with poorer survival, particularly during the first 5 years, although the difference was not statistically significant after 10 years of follow-up (p=0.36). The prevalence of TNT was higher in H (10.3%) than NHW (6.6%) women, and H also tended to poorer survival than NHW women (p=0.17). In multivariate-adjusted models, women with a TNT phenotype had a 26% increased risk of death (HR=1.26 95% CI 0.62−2.6). In NHW women, the risk was 12% (HR=1.12 95% CI 0.43−2.9). Among H women, those with a TNT phenotype had a 17% increased risk of death (HR=1.17 95% CI 0.35−3.8) while those with ER-/PR-/Her2+ had a 46% increase (HR= 1.46 95% CI 0.40−5.3). Discussion: Although this analysis is limited by small numbers, the results suggest that H women may have worse 10-year survival rates than NHW women and that women with TNT have a higher risk of death regardless of ethnicity. These differences in survival could be due to a higher rate of recurrence or issues related to treatment. This study suggests that there is an ethnic disparity in survival by HR subtypes that should be examined in a larger population based study. Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-14-08.