Racial and ethnic differences in breast cancer incidence, clinicopathological features and survival by age and breast cancer subtypes

Abstract Background: Age and ethnicity are important factors in breast cancer (BC) disparities and outcome. However, studies examining both racial and age-related disparities are scarce. We sought to determine differences in epidemiological and clinicopathological characteristics of breast cancer between races in age-specific cohorts. Methods: Gulf Centre for Cancer Registration database and King Faisal Specialist Hospital and Research Center BC registry database for Saudi/Arab women (n=4,206) and Cancer Incidence in Five Continents Volume XI reports, and Surveillance, Epidemiology, and End Results for African-American and non-Hispanic White women with BC were used. Results: Early onset BC (age < 50 years) was more prevalent among Arab women (63%) compared with African-American women (29%) and White-American women (21%). Young Arab and African-American women had more estrogen/progesterone receptor negativity than young White-American women. The triple negative and (HER2)+/(HR)– BC subtypes were more prevalent among young Arab women compared to African-American and White women. The Arab women had the worst prognosis, especially among young women cohort. The differences persisted even after stratification to aggressive BC subtypes. The age-standardized incidence rate was significantly higher in developed countries than in Arab countries within the elderly-women cohort, but was comparable in the young women cohort. Conclusions: While young Arab and Black women had significantly higher frequency of hormonal negativity than White women, Arab women showed significantly higher prevalence of HER2+/HR- and TNBC subtypes than Black and White women. The racial/ethnic differences were more pronounced in the young women cohort. Citation Format: Dilek Colak, Olfat Al-Harazi, Hala Khalil, Maha M. Aleid, Amal N. Almadouj, Sukina Qanbar, Dahish S. Ajarim, Ibrahim H. Kaya, Ali S. Al-Zahrani. Racial and ethnic differences in breast cancer incidence, clinicopathological features and survival by age and breast cancer subtypes [abstract]. In: Proceedings of the 15th AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2022 Sep 16-19; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2022;31(1 Suppl):Abstract nr C114.