TOPLINE

Breast cancer incidence increased rapidly across Asian American, Native Hawaiian, and Pacific Islander ethnic groups in a population-based study of women diagnosed with invasive breast cancer between 2000 and 2022. Among the largest increases reported in women from these ethnic groups were incidences in those younger than 50 years and of distant-stage disease and triple-negative tumors, specifically.

METHODOLOGY

• The incidence rates of breast cancer have historically varied widely across Asian American, Native Hawaiian, and Pacific Islander ethnic groups, but recent national trends have not been updated with detailed ethnicity data.
• Researchers analyzed data from 148,608 Asian American, Native Hawaiian, and Pacific Islander women (29.8% aged < 50 years and 70.2% aged ≥ 50 years at diagnosis) with invasive breast cancer between January 2000 and December 2022. The data came from 14 US states covered by the National Cancer Institute Surveillance, Epidemiology, and End Results (SEER) Program.
• Participants were disaggregated into seven Asian American ethnic groups (Asian Indian or Pakistani, Chinese, Filipino, Japanese, Korean, Laotian or Kampuchean, and Vietnamese), comprising 93.4% of the study population, and two Native Hawaiian and Pacific Islander groups (Native Hawaiian and Guamanian, Chamorro, or Samoan), making up the remaining 6.6%.The Other Asian and Asian Not Otherwise Specified group represented 8.1% of all Asian American patients, and the Other Pacific Islander and Pacific Islander Not Otherwise Specified group represented 22.5% of all Native Hawaiian and Pacific Islander patients.
• The analysis included age-adjusted incidence rates per 100,000 women, stratified by age at diagnosis, stage (localized, regional, or distant), and molecular subtype (hormone receptor [HR]-positive and ERBB2-negative, HR-negative and ERBB2-positive, HR-positive and ERBB2-positive, and HR-negative and ERBB2-negative [triple-negative breast cancer]).
• Overall, 63.9% of cancers were localized, and 66.6% were HR-positive and ERBB2-negative.

TAKEAWAY

• Incidence rates per 100,000 women varied across the groups, ranging from 54.1 in Laotian or Kampuchean women to 177.2 in Native Hawaiian women. Among those younger than 50 years, incidence rates per 100,000 women ranged from 26.3 among Laotian and Kampuchean women to 69.2 among Japanese women.
• Breast cancer incidence among Asian American women increased 2.34% annually from 2012 to 2022, exceeding increases observed in other racial and ethnic groups. Native Hawaiian and Pacific Islander women experienced a steady increase of 0.84% annually from 2000 to 2022.
• Among women younger than 50 years, incidence increased by 2.88% per year in the aggregated Asian American, Native Hawaiian, and Pacific Islander group from 2016 to 2022, reaching rates comparable to non-Hispanic White women by 2021-2022; the largest increase was noted among Chinese women (2017-2022 annual percentage change [APC], 4.57%). Among women aged 50 years or older, incidence increased by 2.52% annually since 2016, representing the fastest increase of any US racial or ethnic group in that age category.
• From 2004 to 2021, Asian American, Native Hawaiian, and Pacific Islander females experienced increasing trends of breast cancer across all three stages, with the largest increase seen for the distant stage (APC, 3.04%). Distant-stage breast cancer increased most rapidly among Asian Indian and Pakistani women (APC, 4.02%) and Chinese women (APC, 4.52%).
• HR-positive and ERBB2-negative cancer rose significantly in all Asian American ethnic groups, except Laotian and Kampuchean women, with the largest increases observed among Korean women (APC, 6.00%). Triple-negative breast cancer incidence increased among Asian American, Native Hawaiian, and Pacific Islander women (APC, 4.35%) from 2016 to 2022.

IN PRACTICE

“This population-based, descriptive, cross-sectional study covering a more than 20-year period found rapid recent increases in breast cancer incidence in Asian American, Native Hawaiian, and Pacific Islander women, especially for early-onset breast cancer,” the authors of the study wrote.

“That nearly all examined Asian American populations showed increasing early-onset breast cancer trends should prompt greater attention from clinicians, researchers, and cancer control programs,” said Gregory S. Calip, University of Southern California Alfred E. Mann School of Pharmacy and Pharmaceutical Sciences, Los Angeles; Kent F. Hoskins, University of Illinois College of Medicine, Chicago; and Jenny S. Guadamuz, School of Public Health, University of California, Berkeley, in an invited commentary. “The core lesson of this study is not only that breast cancer incidence is rising but also that aggregation can hide urgency and that without data equity, cancer equity will remain out of reach.”

SOURCE

The study, led by Scarlett Lin Gomez, PhD, MPH, Greater Bay Area Cancer Registry, Department of Epidemiology and Biostatistics, University of California, San Francisco, was published online on June 30 in JAMA Network Open.

LIMITATIONS

Some cases were classified as other or not otherwise specified, which may have led to underestimation in defined ethnic groups. Race and ethnicity misclassification may have affected some estimates.

DISCLOSURES

The study received support from the Breast Cancer Research Foundation, with Gomez serving as a principal investigator. Funding was also provided through contracts with the National Cancer Institute SEER Program for the University of California, San Francisco, and the University of Hawaii, as well as the Surveillance Research Program, Division of Cancer Control and Population Sciences of the National Cancer Institute. The authors reported having no relevant conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.