Disparities in survival after breast cancer persisted across racial/ethnic groups even after researchers adjusted for multiple demographics, such as patients’ education and the socioeconomic status of the neighborhood in which they lived, according to data presented at the Fifth AACR Conference on The Science of Cancer Health Disparities, held here Oct. 27-30, 2012.
“We learned that the effects of neighborhood socioeconomic status differed by racial/ethnic group. When simultaneously accounting for race/ethnicity and socioeconomic status, we found persistent differences in survival within and across racial/ethnic groups,” said Salma Shariff-Marco, Ph.D., M.P.H., a researcher at the Cancer Prevention Institute of California in Fremont.
Shariff-Marco and colleagues studied data from 4,405 patients with breast cancer who had participated in one of two population-based studies undertaken in the San Francisco Bay Area. Participants included 1,068 non-Latina whites, 1,670 Latinas, 993 African-Americans and 674 Asian-Americans.
All-cause survival was worse for African-Americans and better for Latinas and Asian-Americans compared with non-Latina whites after adjusting for age, study and tumor characteristics. When the researchers additionally adjusted for treatment and reproductive and lifestyle factors, they found that African-Americans had similar survival rates to non-Latina whites, but the survival rates of Latinas and Asian-Americans remained better.
Researchers also evaluated disparities in survival while considering racial/ethnic and socioeconomic status interactions. Compared with non-Latina whites with high education and high neighborhood socioeconomic status, worse survival was seen for African-Americans with low neighborhood socioeconomic status (regardless of education) and better survival was seen among Latinas with high neighborhood socioeconomic status (regardless of education) and Asian-Americans with high education and high neighborhood socioeconomic status.
The researchers noted that certain groups who were identified as having better or worse survival would benefit from further study to understand their risk profiles and target specific interventions.
“Understanding and addressing potential barriers to better survival are needed for groups with worse survival,” Shariff-Marco said. “One program that may be useful is patient navigation to ensure that these women are able to access and navigate the health care system. Sharing these findings with the broader public health community (e.g., health educators, community-based organizations and leaders) will also be helpful.”
Understanding racial/ethnic and multilevel socioeconomic disparities in survival after breast cancer
Background: Racial/ethnic disparities in survival after breast cancer persist, even after accounting for socioeconomic status (SES); however, few studies have evaluated both individual and neighborhood SES jointly. In particular, evaluating the interactions between multiple components of social status (e.g., race/ethnicity, SES, nativity) simultaneously may help us to better understand the survival disparities. Our hypothesis is that social status measures jointly influence health.
Methods: Our study included 4,405 breast cancer patients diagnosed in the period 1995-2008, representing non-Latina whites (n=1068), Latinas (n=1670), African Americans (n=993) and Asian Americans (n=674) from two population-based studies in the San Francisco Bay Area. Using stage-stratified Cox proportional hazards models, we assessed the association between race/ethnicity and all-cause and breast cancer-specific survival, after adjusting for education, neighborhood SES (nSES), and other prognostic factors (e.g., treatment, reproductive, and lifestyle factors). We also examined the interaction of 3 social status variables (race/ethnicity, education (low=≤HS graduation/high=≥ some college) and neighborhood SES (low=quintiles 1-3/high=quintiles 4-5)) on survival.
Results: All cause survival was worse for African Americans (HR=1.37, 95% CI=1.14-1.64) and better for Latinas (HR=0.77, 95% CI=0.64-0.92) and Asian Americans (HR=0.83, 95% CI=0.65-1.08) compared to non-Latina whites after adjusting for age, study, tumor characteristics. Additionally adjusting for treatment, reproductive and lifestyle factors attenuated associations for African Americans, such that they had similar survival to non-Latina whites, whereas the better survival observed among Latinas and Asian Americans remained. Social status disparities in survival after breast cancer were also evident in models considering the racial/ethnic and SES interactions. Compared to high education/high nSES non-Latina whites, all-cause survival was worse for low education/low nSES non-Latina whites, low nSES African Americans (regardless of education), and low education/low nSES Asian Americans, whereas all-cause survival was better for high nSES Latinas (regardless of education) and high education/high nSES Asian Americans. Accounting for additional prognostic factors attenuated associations for low education/low nSES Whites and low education/low nSES Asian Americans. Similar patterns were observed for breast cancer-specific survival.
Discussion: Racial/ethnic disparities in survival after breast cancer persisted after adjusting for education, neighborhood SES and other prognostic factors. Our findings of racial/ethnic disparities in survival are consistent with prior literature. When simultaneously accounting for multiple social statuses, we found that disparities existed within and across racial/ethnic groups. We were able to identify specific subgroups based on multiple dimensions of social status that are at increased and decreased risk of mortality (e.g., African Americans in low SES neighborhoods, Asians with low education and low nSES, and Latinas in high nSES). These subpopulations would benefit from further study to better understand their risk profiles and for targeting specific interventions.
Salma Shariff-Marco, Juan Yang, Meera Sangaramoorthy, Andrew Hertz, Esther M. John, Jocelyn Koo, David O. Nelson, Clayton Schupp, Theresa H.M. Keegan, Scarlett Lin Gomez. Cancer Prevention Institute of California, Fremont, CA.
American Association for Cancer Research