Race & Ethnicity in Stage-specific Breast Cancer Survival

Institution: Beckman Research Institute of the City of Hope
Investigator(s): Katherine DeLellis Henderson, Ph.D. -
Award Cycle: 2009 (Cycle 15) Grant #: 15QB-8203 Award: $32,953
Award Type: SRI Request for Qualifications-RFQ
Research Priorities
Community Impact of Breast Cancer>Disparities: eliminating the unequal burden of breast cancer



Initial Award Abstract (2009)

While breast cancer mortality has been steadily decreasing since 1990, this decline has not been realized equally among all racial/ethnic groups in the U.S. For example, from 1995-2004, SEER data indicates a 2.4% yearly decrease in mortality for white and Hispanic/Latina women, but only a 1.6% yearly decrease for African Americans. Although rates are decreasing over time among both African Americans and whites, the rate among whites is decreasing faster, so the net effect has been a widening disparity in breast cancer mortality. While differences in stage at diagnosis are important in understanding these survival disparities, even when stage is controlled for, a persistent and growing survival disparity emerges. The reasons for this are not clear.

Among other racial/ethnic groups even less is known about the factors affecting survival rates. Attempts to fill this knowledge gap are hindered because specific racial/ethnic subgroups are often aggregated to achieve sufficient numbers in studies, but this procedure may be obscuring important trends and factors specific to certain subgroups.

The cohort and case-control studies overcome this problem by collecting detailed information on each individual through the use of a variety of survey instruments and often blood and/or fluid sampling. However, existing California cohort and case-control studies do not have sufficient numbers of different racial and ethnic populations to allow inter-group comparisons.

Representatives of the California Teachers Study and other studies are collaborating to determine whether it is feasible to pool data from our existing California case-control and cohort studies to investigate critical issue(s) in stage-specific survival that could not be answered by any of the studies alone. This feasibility study will review and evaluate:
1. The comparability of survey instruments
2. The compatibility of data sets (platforms, variables, etc.),
3. The quality and type(s) of additional data that could be linked to data from study participants (e.g. records from medical databases).
4. The specific research question(s) not answered by the individual studies that could be answered by pooling data from these studies.

The proposed goal of this study is a full research proposal to investigate unique questions about disparities and breast cancer survival in California.




Final Report (2010)

While breast cancer mortality has been steadily decreasing since 1990, this decline has not been realized equally among all racial/ethnic groups in the U.S. For example, from 1995-2004, SEER data indicates a 2.4% yearly decrease in mortality for white and Hispanic/Latina women, but only a 1.6% yearly decrease for African Americans. Although rates are decreasing over time among both African Americans and whites, the rate among whites is decreasing faster, so the net effect has been a widening disparity in breast cancer mortality. While differences in stage at diagnosis are important in understanding these survival disparities, even when stage is controlled for, a persistent and growing survival disparity emerges. The reasons for this are not clear.

Among other racial/ethnic groups even less is known about the factors affecting survival rates. Attempts to fill this knowledge gap are hindered because specific racial/ethnic subgroups are often aggregated to achieve sufficient numbers in studies, but this procedure may be obscuring important trends and factors specific to certain subgroups.

The cohort and case-control studies overcome this problem by collecting detailed information on each individual through the use of a variety of survey instruments and often blood and/or fluid sampling. However, existing California cohort and case-control studies do not have sufficient numbers of different racial and ethnic populations to allow inter-group comparisons.

Representatives of the LA County Asian American Breast Cancer Study, the Pathways and Life after Cancer Epidemiology Studies, the California Teachers Study, the Women’s CARE Study, the Multi-Ethnic Cohort, and the SF Bay Area Breast Cancer Study collaborated for more than a year, holding two in-person meetings and monthly phone calls. They found that certain data were available and comparable in all or many of the participating studies data sets and together identified unique questions about disparities and breast cancer survival in California to investigate. Their final product was a proposal for CBCRP funding to create the California Breast Cancer Survivorship Consortium (CBCSC), consisting of seven California-based breast cancer studies with over 16,000 breast cancer cases, including 2603 African Americans, 2113 Asian Americans, 2582 Latinas, and 9306 non-Latina Whites.

The proposal was funded (see CBCRP awards 16ZB-8001, -8002, -8003, -8004, and -8005) to pool and analyze data to explore factors that may impact racial/ethnic differences in stage-specific breast cancer survival. These factors differ by race/ethnicity are suspected of influencing breast cancer mortality. The consortium will pursue four studies to assess: 1) neighborhood variations in race/ethnicity and in socioeconomic status, and how these may interact with individual exposure factors to contribute to differences in mortality; 2) how the racial/ethnic differences in physical activity impact differences in mortality; 3) the impact of body mass index, weight gain and waist/hip ratio on racial/ethnic differences in breast cancer mortality; and 4) how diabetes, hypertension and heart disease affect survival in different racial/ethnic groups.