Abstract P4-03-24: State variation in racial and ethnic disparities in triple-negative breast cancer rates: NPCR-SEER incidence data, 2015-2019
Authors: Sung Hyuna , Wiese Daniel , Jatoi Ismail , Jemal Ahmedin 
Published: March 2023

Abstract
Background: Triple-negative breast cancer (TNBC) (i.e., estrogen receptor-negative, progesterone receptor-negative, and human epidermal growth factor receptor type 2-negative) is an aggressive subtype of breast cancer, more frequently diagnosed among non-Hispanic Black women than other racial/ethnic groups in the United States. TNBC risk also varies by location, but limited data exist for state-level variation in the racial/ethnic disparities in TNBC risk. Methods: Data for TNBC diagnosed at all ages during 2015-2019 were obtained from the National Program of Cancer Registries and Surveillance, Epidemiology & End Results for racial/ethnic groups classified as non-Hispanic American Indian/Alaska Native (AIAN), non-Hispanic Asian or Pacific Islander (API), non-Hispanic Black (Black), Hispanic, or non-Hispanic White (White). State-specific incidence rates were available for 8, 23, and 36 states for AIAN, API, and Hispanic women, respectively, and 38 states and Washington, D.C. for Black women and 50 states and Washington, D.C. (hereafter referred to collectively as “states”) for White women. State-specific rates were compared within and between racial/ethnic groups using incidence rate ratios (IRR). Results: Nationally, the age-standardized incidence rate of TNBC was the highest among Black women (25.1 per 100,000), followed by White (12.9 per 100,000), AIAN (11.1 per 100,000), Hispanic (11.1 per 100,000), and API (9.0 per 100,000) women. The highest state-specific rates were found among Black women in Delaware, Missouri, and Louisiana (&gt;30 per 100,000) and the lowest rates were among API women in Oregon and Pennsylvania (&lt; 7 per 100,000). State variations within a population were relatively larger among AIAN (2.8-fold) and Hispanic (2.3-fold) women, and smaller among White women (1.65-fold). Compared with White women, Black women had a higher rate of TNBC in all 39/39 states with the greatest IRRs in Delaware (2.31, 95%CI=1.90-2.81), Missouri (2.28, 95%CI=2.08-2.50), and Louisiana (2.20, 95%CI=2.02-2.38) and the lowest IRRs in Minnesota (1.38, 95%CI=1.12-1.68) and Colorado (1.38, 95%CI=1.12-1.68). In contrast, API women had a lower rate than White women in 22/23 states, except for Nevada, with the lowest IRR in Oregon (0.50, 95%CI=0.34-0.70) and the highest IRR in New York (0.82, 95%CI=0.75-0.90). The rate among Hispanic compared with White women did not differ statistically significantly in 23/36 states but was lower in 12/36 states, with the lowest IRR in Ohio (0.57, 95%CI=0.43-0.74), and higher in Massachusetts (1.21, 95%CI=1.04-1.39). The rate among AIAN compared with White women did not differ in 5/8 states but was lower in Arizona (0.53, 95%CI=0.38-0.73) and North Carolina (0.68, 95%CI=0.46-0.96), and higher in Oklahoma (1.30, 95%CI=1.09-1.54). Conclusions: State variations in TNBC incidence rates both within and between populations are substantial, signifying the important role of potentially modifiable risk factors in determining the risk of TNBC by state and race/ethnicity. This finding highlights the need for more research to identify factors contributing to these variations to develop more effective preventive measures. Meanwhile, to mitigate the impact of the disproportionate burden of TNBC across states and racial/ethnic groups, universal access to screening modalities and timely, guideline-concordant treatments is essential.
Citation Format: Hyuna Sung, Daniel Wiese, Ismail Jatoi, Ahmedin Jemal. State variation in racial and ethnic disparities in triple-negative breast cancer rates: NPCR-SEER incidence data, 2015-2019 [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-03-24.