Breast cancer treatment and ethnicity in British Columbia, Canada

Racial and ethnic disparities in breast cancer incidence, stage at diagnosis, survival and mortality are well documented; but few studies have reported on disparities in breast cancer treatment. This paper compares the treatment received by breast cancer patients in British Columbia (BC) for three ethnic groups and three time periods. Values for breast cancer treatments received in the BC general population are provided for reference.

Information on patients, tumour characteristics and treatment was obtained from BC Cancer Registry (BCCR) and BC Cancer Agency (BCCA) records. Treatment among ethnic groups was analyzed by stage at diagnosis and time period at diagnosis. Differences among the three ethnic groups were tested using chi-square tests, Fisher exact tests and a multivariate logistic model.

There was no significant difference in overall surgery use for stage I and II disease between the ethnic groups, however there were significant differences when surgery with and without radiation were considered separately. These differences did not change significantly with time. Treatment with chemotherapy and hormone therapy did not differ among the minority groups.

The description of treatment differences is the first step to guiding interventions that reduce ethnic disparities. Specific studies need to examine reasons for the observed differences and the influence of culture and beliefs.