Abstract A04: The California Breast Cancer Survivorship Consortium (CBCSC): Prognostic factors associated with racial/ethnic differences in breast cancer survival
Authors: Vigen Cheryl LP , Gomez Scarlett Lin , Sposto Richard , Lu Yani , Kwan Marilyn L. , John Esther M. , Monroe Kristine R. , Keegan Theresa HM , Shariff-Marco Salma , Kurian Allison W. , Cheng Iona , Caan Bette J. , Lee Valerie S. , Roh Janise M. , Sullivan-Halley Jane , Bernstein Leslie , Wu Anna H. 
Published: January 2014

Background: Racial/ethnic disparities in mortality among US breast cancer patients are well documented. Using 2000-2006 data from Surveillance, Epidemiology, and End Results (SEER) registries, relative risk [95% confidence interval (CI)] of breast cancer-specific mortality relative to non-Latina Whites was significantly higher for African Americans (1.5 [1.4,1.6]) and Latinas (1.1 [1.0,1.2]), and non-significantly lower (0.9 [0.8,1.0]) for Asian Americans after adjusting for diagnosis age, SEER registry, disease stage, estrogen/progesterone receptor (ER/PR) status, county level poverty/education index, and other factors (Breast Cancer Res Treat, 127:729–738). Reasons for these differences are not well-understood; individual lifestyle factors may explain these differences, but current knowledge of the role of lifestyle in disease prognosis is limited for African Americans, Latinas and Asian Americans.

Methods: The CBCSC assembled interview and cancer registry data from six California-based breast cancer etiology or prognosis studies, resulting in 12,210 breast cancer patients diagnosed with primary invasive breast cancer (6501 non-Latina Whites, 2060 African Americans, 2032 Latinas, 1505 Asian Americans, 112 others) between 1993 and 2007. Clinical characteristics and mortality data were obtained from the California Cancer Registry (CCR). Demographics (education, birthplace, migration), family history of breast cancer, parity, smoking, alcohol consumption, and other interview data were harmonized and pooled. Cox proportional hazards regression of overall and breast-cancer specific mortality were used to estimate racial/ethnic differences in stage-specific survival.

Results: Frequency of adverse tumor characteristics (stage, differentiation, ER/PR status, nodal status, tumor size) were highest in African Americans, followed by Latinas, Asian Americans and non-Latina Whites, generally in that order. Latinas had lower education and higher parity than other racial/ethnic groups, whereas family history of breast cancer and alcohol consumption were highest in non-Latina Whites, and smoking was highest in African Americans. In total, 3047 deaths (1570 breast cancer-related) were observed after a mean (SD) follow-up of 8.3 (3.5) years. Compared to non-Latina Whites, the hazard ratio (HR) and 95% CI for breast cancer specific mortality was 1.15 [0.98,1.34] for African Americans, 0.77 [0.64,0.92], for Latinas, and 0.57 [0.36,0.92], for Asian Americans (adjusting for age and characteristics available from the tumor registry). HRs were slightly attenuated by further adjustment for education, migration, smoking and other factors (1.12 [0.95,1.31], 0.84 [0.69,1.02], 0.61 [0.38,0.99], respectively). Analyses are ongoing to determine the effect of neighborhood contextual factors, physical activity, body size, and comorbidities on racial/ethnic disparities in breast cancer survival.

Conclusions: The CBCSC is a unique resource of a large and racially/ethnically diverse breast cancer cohort that will allow joint consideration of a variety of clinical, lifestyle, and contextual factors in explaining the long-standing disparities in breast cancer survival.

Funded by: California Breast Cancer Research Program Special Research Initiative (16ZB-8004).

Citation Format: Cheryl LP Vigen, Scarlett Lin Gomez, Richard Sposto, Yani Lu, Marilyn L. Kwan, Esther M. John, Kristine R. Monroe, Theresa HM Keegan, Salma Shariff-Marco, Allison W. Kurian, Iona Cheng, Bette J. Caan, Valerie S. Lee, Janise M. Roh, Jane Sullivan-Halley, Leslie Bernstein, Anna H. Wu. The California Breast Cancer Survivorship Consortium (CBCSC): Prognostic factors associated with racial/ethnic differences in breast cancer survival. [abstract]. In: Proceedings of the Eleventh Annual AACR International Conference on Frontiers in Cancer Prevention Research; 2012 Oct 16-19; Anaheim, CA. Philadelphia (PA): AACR; Cancer Prev Res 2012;5(11 Suppl):Abstract nr A04.