Late-stage diagnosis of breast cancer among Asian and Pacific Islander subgroups

Background/significance: A late stage diagnosis of breast cancer can indicate inadequate screening. It has been reported previously that Asian and Pacific Islander (API) women have fewer late-stage diagnoses than women of other race/ethnicities, but studies rarely examine API subgroups. Objective/Purpose: We previously found that the odds of late-stage diagnosis of breast cancer differed by API ethnicity in Orange County, California. In this study we explore stage of diagnosis for API subgroups in California. Methods: Primary breast cancers were identified using the statewide California Cancer Registry for 1991-2005. We categorized breast cancer cases as early (confined to the breast) or late stage. Race/ethnicity was abstracted from the patients' medical records. Logistic regression was used to calculate the odds of late stage diagnosis, adjusting for age and year of diagnosis. Results: Of 25,177 API women with breast cancer in California, 7,799 (31%) were diagnosed at a late stage. In regression analysis, API had significantly reduced odds of being diagnosed late stage, compared to non-Hispanic white women. Among API ethnicities, Chinese (OR=0.88, 95% CI = 0.84, 0.94) and Japanese (OR=0.83, 95% CI = 0.77, 0.89) breast cancer patients also had significantly reduced odds of late stage diagnosis compared to non-Hispanic whites, but Pacific Islanders (OR=1.37, 95% CI = 1.17, 1.61) and South Asians (OR=1.28, 95% CI = 1.14, 1.44) had significantly increased risks. Discussion/Conclusions: The likelihood of being diagnosed with breast cancer at a late-stage differed by API subgroup; Pacific Islander and South Asian women were at higher risk.