Stress and breast cancer risk among Asian American females: The CRANE Study

Background: Breast cancer incidence rates among Asian American (AA) women have risen rapidly, 2.3% annually since 2012, far outpacing the overall US trend. The increase is particularly stark for early-onset cases (<50 years), at 2.9% per year since 2016. Significant increases were observed across nearly all AA groups, stages and subtypes, with especially sharp rises in late-stage and triple-negative breast cancer. Foreign-born AA now face higher risk relative to US-born AA, even after accounting for established risk factors. These evolving patterns point to emerging, unrecognized risk factors. The CRANE Study (Breast C ancer R isk among A sia n Am e ricans) investigates multilevel determinants, from environmental to biological, that drive the contemporary elevated risk in this population. This abstract describes preliminary social stressor results. Methods: The CRANE Study, initiated in 2022, is a population-based case-control study of breast cancer in AA in California. The study integrates epidemiologic data on established and emerging risk factors with geospatial data (including residential histories), cancer registry data, and biospecimens (saliva and hair), alongside access to medical records and tumor specimens. AA women with recently-diagnosed breast cancer are identified through the Greater Bay Area and Los Angeles County cancer registries. Controls, matched to cases by ethnicity, age, and region, are recruited using multiple modalities to represent the population at risk. Results: To date, 317 cases and 368 controls have been enrolled (39% Chinese, 18% Filipina, 9% Japanese, and 8% each Korean, South Asian, and Southeast Asian). Among cases, 48% were younger than age 50 at diagnosis, ranging from 16% among Japanese to 71% among Koreans. Most were diagnosed at stage I disease (70%). Tumor subtypes included 68% HR+/HER2-, 20% HER2+ (14% among Koreans to 29% among South Asians), and 8.5% triple-negative cancer. Compared to controls, cases were more likely to be foreign-born (72% vs. 54%) and less acculturated (65% vs. 81% English proficient), and have higher BMI (20% vs. 14% BMI > 27.5) and later menarche (50% vs. 45% at ≥13 years). However, cases reported lower levels of stress (20% vs 24% in the highest quartile of immigrant stress) and racism (15% vs. 22% in the highest quartile of anti-Asian racism) compared to controls. Despite reporting fewer stressors, more cases than controls expended higher levels of effortful coping on the John Henryism scale (29% vs. 24% in the highest quartile). Conclusions: The CRANE Study provides a unique and timely platform to investigate how environmental, social, and biological factors interact to shape breast cancer risk in this population. By focusing on AA, who are experiencing notable increases in early-onset and triple-negative breast cancers, CRANE aims to identify novel risk factors and pathways that may help explain emerging breast cancer trends in both AA and the broader US population.