2022 - Influence of Ethnicity and Birthplace on Breast Cancer Clinical Features, Treatment and Survival among Texas Women

A. N. Chavana¹, H. Mekdash², N. B. Alam³, R. Pettit⁴, and M. S. Ludwig²; ¹Baylor College of Medicine, Houston, TX, ²Department of Radiation Oncology, Dan L. Duncan Comprehensive Cancer Center, Baylor College of Medicine, Houston, TX, ³Department of Radiation Oncology, Mayo Clinic, Rochester, MN, ⁴Department of Clinical Pathology, Mass General Brigham, Boston, MA

Purpose/Objective(s): Birthplace (United States vs foreign born) has a significant impact on incidence and survival following diagnosis with various malignancies; however, there is no consensus on breast cancer. Our objective was to determine the impact of birthplace on presentation, clinical features, treatment, and survival of Texas women diagnosed with primary invasive breast cancer. Materials/

Methods: This is a single-state retrospective cohort study. Females (n=290,656) enrolled in the Texas Cancer Registry with a diagnosis of first or primary invasive breast cancer between 1995-2018 were included. Demographic and clinical parameters (pathology, receptor status, treatment, and vital status at last follow up) were obtained from the database. Missing birthplace data was estimated by multiple imputations using a Monte Carlo Markov Chain (MCMC) algorithm after meeting the missing at random (MAR) assumption. The associations among categorical variables were examined using Chi square or Fisher’s exact tests. Multivariate logistic regression was used to examine the relationship between the identified predictors and survival as the study outcome. Odd ratios with 95% confidence interval were reported, with p<0.05 denoting significance.
Results: Overall, most patients (n=290,656) were 46-64 years old at diagnosis (152,071; 52.3%), had ductal carcinoma (202,776; 69.8%), grade 2 diagnosis (101, 067; 34.8%), and were born in the United States (US) (269,066; 92.6%). Foreign born Hispanic (4.7%) and Asian women (3.3%) had significantly more metastatic disease at presentation compared to US born counterparts (2.7% and 2.1%, respectively). There was marginally more grade 3 disease among foreign born Hispanic (35.7%) and Asian women (32.6%) compared to US born counterparts, however, there was substantially more grade 3 disease when compared to US born White women (27.5%). Hispanic (2.1%) and Asian women (2.5%) presented with more hormone receptor negative disease (estrogen and progesterone negative) compared to White women (1.3%). Regardless of birthplace, Asian women (25.7%) were more likely to receive radiation compared to Hispanic (22.3%) and White women (24%). Most notably, foreign born Hispanic (HR 1.482, 95% CI: 1.419-1.548, p<0.001) and Asian women (HR 1.172, 95% CI: 1.058-1.299, p=0.002) have significantly increased risk of death due to breast cancer compared to their US born counterparts and foreign-born White women.
Conclusion: At diagnosis, foreign born Hispanic and Asian women present with more metastatic disease with Asian women receiving more radiation, regardless of birthplace. Additionally, foreign born Hispanic and Asian women have increased risk of death due to breast cancer. This work highlights the impact of birthplace and ethnicity on an individual’s clinical presentation, treatment, and risk of breast cancer mortality.