Abstract 4232: Multivariate analysis of breast cancer patients showing superior outcome in Hispanics compared to non-Hispanics
Authors: Khoobehi Aurash , Shi Runhua , Burton Amanda , Burton Gary V. 
Published: August 2018

Background

Breast cancer incidence and mortality varies relative to ethnicity and socioeconomic status. Prior research has shown that Hispanics appear to have a lower mortality rate from breast cancer when compared to Non-Hispanic Blacks (NHB) and Non-Hispanic Whites (NHW). To further delineate the influence of Hispanic ethnicity on breast cancer outcomes, we compared ethnicity and outcome while adjusting for multiple variables using data from the National Cancer Data Base (NCDB) collected between 2004 and 2013.

Methods

Data were analyzed from 984,512 women registered in the NCDB who were diagnosed with stage I to stage IV breast cancer. Overall survival was the primary outcome variable; the primary predictor variable was ethnicity (NHW, NHB, and Hispanic). Variables addressed and adjusted for included: stage, age, Charlson Comorbidity index, estrogen/progesterone receptor (ERPR) status and HER2 receptor status. Multivariate Cox regression was used to investigate the effect of ethnicity on overall survival while adjusting for secondary predictive factors.

Results

The majority of patients were NHW (85.6%), NHB (12.5%), and Hispanic (1.85%). The median overall survival for all patients was greater than 12 years.

Hispanics, compared to NHW, had a higher percentage of patients with triple negative (TN) (7.6 vs 5.6%), HER2 positive (19.3 vs 14.2%), and stage III/IV (23.1 vs 15.7%). In univariate analysis, the hazard ratio (HR) of death in Hispanics, compared to NHW, was lower for stage III (0.744), stage IV (0.842), HER2 positive (0.748) and TN (0.862) patients (all p-value &lt;0.05). Hispanics, compared to NHW, had a lower percentage of patients with ERPR positive (77.3 vs 82.9%) and stage I (39.3 vs 52.3%). However, the HR of death in Hispanics, compared to NHW, was lower for stage I (0.607) and ERPR positive (0.779) patients (all p-value &lt;0.05).

All patients with a Charlson score of 1 or more, regardless of ethnicity, are 65% more likely to die compared to patients with no co-morbidities. Triple negative patients are 2.5 times more likely to die compared to patients of non-TN status. Patients that are stage II, III, and IV are 1.9, 4.6, and 19.2 times more likely to die than patients with stage I disease, respectively.

In multivariate Cox regression, effects of ethnicity on survival were significant. Hispanic patients were 17% less likely and NHB patients were 34% more likely to die when compared to NHW breast cancer patients.

Conclusion

The Hispanic, breast cancer population has a statistically significant better survival than NHW patients regardless of stage, age, co-morbidities, or receptor (ERPR, HER2 or TN) status. These results indicate that Hispanic ethnicity is a predictor of superior patient outcomes. Further investigation will be required to delineate the factors which contribute to this outcome difference.

Citation Format: Aurash Khoobehi, Runhua Shi, Amanda Burton, Gary V. Burton. Multivariate analysis of breast cancer patients showing superior outcome in Hispanics compared to non-Hispanics [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4232.