Second primary cancer risks according to race and ethnicity among U.S. breast cancer survivors

Carolyn Brandt; Jacqueline B Vo; Gretchen L Gierach; Iona Cheng; Vanessa N Torres; Wayne R Lawrence; Lauren E McCullough; Lene H S Veiga; Amy Berrington de González; Cody Ramin

doi:10.1002/ijc.34971

Second primary cancer risks according to race and ethnicity among U.S. breast cancer survivors

Int J Cancer. 2024 Apr 29. doi: 10.1002/ijc.34971. Online ahead of print.

Authors

Carolyn Brandt¹, Jacqueline B Vo¹, Gretchen L Gierach¹, Iona Cheng^{2

3

4}, Vanessa N Torres⁵, Wayne R Lawrence¹, Lauren E McCullough⁶, Lene H S Veiga¹, Amy Berrington de González^{1

7}, Cody Ramin^{1

5}

Affiliations

¹ Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, Maryland, USA.
² Department of Epidemiology and Biostatistics, University of California San Francisco, San Francisco, California, USA.
³ Helen Diller Family Comprehensive Cancer Center, University of California San Francisco, San Francisco, California, USA.
⁴ Greater Bay Area Cancer Registry, University of California San Francisco, California, USA.
⁵ Cancer Research Center for Health Equity, Cedars-Sinai Medical Center, Los Angeles, California, USA.
⁶ Department of Epidemiology, Emory University, Atlanta, Georgia, USA.
⁷ Division of Genetics and Epidemiology, The Institute of Cancer Research, London, UK.

PMID: 38685564
DOI: 10.1002/ijc.34971

Abstract

Breast cancer survivors have an increased risk of developing second primary cancers, yet risks by race and ethnicity have not been comprehensively described. We evaluated second primary cancer risks among 717,335 women diagnosed with first primary breast cancer (aged 20-84 years and survived ≥1-year) in the SEER registries using standardized incidence ratios (SIRs; observed/expected). SIRs were estimated by race and ethnicity compared with the racial- and ethnic-matched general population, and further stratified by clinical characteristics of the index breast cancer. Poisson regression was used to test for heterogeneity by race and ethnicity. SIRs for second primary cancer differed by race and ethnicity with the highest risks observed among non-Hispanic/Latina Asian American, Native Hawaiian, or other Pacific Islander (AANHPI), non-Hispanic/Latina Black (Black), and Hispanic/Latina (Latina) survivors and attenuated risk among non-Hispanic/Latina White (White) survivors (SIR_AANHPI = 1.49, 95% CI = 1.44-1.54; SIR_Black = 1.41, 95% CI = 1.37-1.45; SIR_Latina = 1.45, 95% CI = 1.41-1.49; SIR_White = 1.09, 95% CI = 1.08-1.10; p-heterogeneity<.001). SIRs were particularly elevated among AANHPI, Black, and Latina survivors diagnosed with an index breast cancer before age 50 (SIRs range = 1.88-2.19) or with estrogen receptor-negative tumors (SIRs range = 1.60-1.94). Heterogeneity by race and ethnicity was observed for 16/27 site-specific second cancers (all p-heterogeneity's < .05) with markedly elevated risks among AANHPI, Black, and Latina survivors for acute myeloid and acute non-lymphocytic leukemia (SIRs range = 2.68-3.15) and cancers of the contralateral breast (SIRs range = 2.60-3.01) and salivary gland (SIRs range = 2.03-3.96). We observed striking racial and ethnic differences in second cancer risk among breast cancer survivors. Additional research is needed to inform targeted approaches for early detection strategies and treatment to reduce these racial and ethnic disparities.

Keywords: breast cancer; cancer survivorship; epidemiology; racial and ethnic disparities; second cancers.

Grants and funding

CP/NCI NIH HHS/United States