Racial Disparities in Breast Cancer Put Some at Greater Risk

October 14, 2015
Kelly Johnson

Regardless of breast cancer subtype or stage, minority women are more likely to be diagnosed with more advanced-stage breast cancer and receive inappropriate treatment, a new study has found.

Lu Chen, MPH

Regardless of breast cancer subtype or stage, minority women are more likely to be diagnosed with more advanced-stage breast cancer and receive inappropriate treatment, a new study has found.

Led by Lu Chen, MPH, researcher in the Public Health Sciences Division at Fred Hutchinson Cancer Research Center, investigators analyzed data of 102,064 women from 18 US population-based cancer registries participating in the Surveillance, Epidemiology, and End Results (SEER) program of the National Cancer Institute.

The data observed included demographic characteristics, disease stage, tumor grade and size, primary treatment, health insurance, tumor subtypes, hormone receptor (HR) status, and HER2 status.

Compared with non-Hispanic white women, all other racial and ethnic groups were more likely to be diagnosed with more advanced breast cancer.

African American women were 40% to 70% more likely to be diagnosed at stage IV across all subtypes, and were more likely to have large tumors and aggressive triple-negative breast cancer.

Hispanic women were 30% to 40% more likely to be diagnosed at stage II or stage III across all subtypes.

White women were more likely to have smaller tumors and less-aggressive HR-positive/HER2-negative subtype of breast cancer.

“We found that there is a consistent pattern of late diagnosis and not receiving recommended treatment for some racial and ethnic groups across all breast cancer subtypes,” Chen said in a statement.

The study, published in Cancer Epidemiology, Biomarkers, & Prevention, also found that minority women were more likely than white women to receive non—guideline-concordant, or inappropriate, treatment across most subtypes of breast cancer.

African American women were 30% to 60% more likely to receive non—guideline-concordant treatment across all subtypes except HR-negative/HER2-positive. Hispanic women were 20% to 40% more likely to receive inappropriate treatment with the exception of HR-negative/HER2-positive subtype and triple-negative cases.

Previous studies have shown that African Americans, Hispanics, and American Indians are less likely to receive appropriate treatment regimens for breast cancer and are more likely to be diagnosed at an advanced stage and die of the disease. While the studies have addressed disparities by disease stage and survival rates, they did not characterize them by subtypes.

“The treatment for breast cancer is currently dependent on the type of breast cancer, defined by the estrogen receptor, progesterone receptor, and HER2 status,” Chen said.

“This is the reason why we think it’s important to look at the disparities by subtype.”

Asians and Pacific Islanders showed no disparities compared with white women in receiving guidance-concordant treatment. American Indian and Alaskan women showed some disparities, but the findings were not statistically significant.

Chen noted that the disparities persisted after adjusting for insurance status, suggesting that other factors contribute to the differences in diagnoses and treatment.

She concluded that changes should be made to screening and subsequent guideline-concordant treatment.

“Given the racial and ethnic disparities, targeted, culturally appropriate interventions in breast cancer screening and care have the potential to reduce the disparities and close the existing survival gaps,” she said.

Chen, L and I. L., C. Advertisement Racial Disparities in Breast Cancer Diagnosis and Treatment by Hormone Receptor and HER2 Status [published online October 13, 2015]. Cancer Epidemiol Biomarkers Prev. doi: 10.1158/1055-9965.EPI-15-0293