Asian Ethnic Subgroup Disparities in Delays of Surgical Treatment for Breast Cancer.

Background: As Asian American breast cancer incidence rises, it is necessary to investigate the origins of differential breast cancer outcomes among Asian ethnic subgroups. This study aimed to examine disparities in delays of breast cancer surgery among Asian ethnic subgroups. Methods: We obtained California Cancer Registry data on female breast cancer diagnoses and treatment from 2012 to 2017. Our main independent variable was patient race and ethnicity, including 6 Asian ethnic subgroups. Dependent variables included time to surgical treatment for breast cancer and receipt of surgical treatment within 30 and 90 days of diagnosis. We conducted multivariable logistic regression to determine the odds of receiving surgery within 30 and 90 days of diagnosis and multivariable Cox proportional hazards regression to determine the risk of prolonged time to surgery. Results: In our cohort of 93 168 breast cancer patients, Hispanic (odds ratio [OR] = 0.86, 95% confidence interval [CI] = 0.82 to 0.89) and non-Hispanic Black (OR = 0.83, 95% CI = 0.78 to 0.88) patients were statistically significantly less likely than non-Hispanic White patients to receive surgery within 30 days of breast cancer diagnosis, whereas Asian Indian or Pakistani (OR = 1.23, 95% CI = 1.09 to 1.40) and Chinese (OR = 1.30, 95% CI = 1.20 to 1.40) patients were statistically significantly more likely to receive surgery within 30 days of diagnosis. Conclusions: This large, population-based retrospective cohort study of female breast cancer patients is the first, to our knowledge, to demonstrate that time to surgical treatment is not equal for all Asians. Distinct differences among Asian ethnic subgroups suggest the necessity of further investigating breast cancer treatment patterns to fully understand and target disparities in breast cancer treatment.