The California Breast Cancer Survivorship Consortium (CBCSC): prognostic factors associated with racial/ethnic differences in breast cancer survival

Abstract

Racial/ethnic disparities in mortality among US breast cancer patients are well-documented. Our knowledge of the contribution of lifestyle factors to disease prognosis is based primarily on non-Latina Whites and is limited for Latina, African American and Asian American women. To address this knowledge gap, the California Breast Cancer Survivorship Consortium (CBCSC) harmonized and pooled interview information (e.g., demographics, family history of breast cancer, parity, smoking, alcohol consumption) from six California-based breast cancer studies and assembled corresponding cancer registry data (clinical characteristics, mortality), resulting in 12,210 patients (6,501 non-Latina Whites, 2,060 African Americans, 2,032 Latinas, 1,505 Asian Americans, 112 other race/ethnicity) diagnosed with primary invasive breast cancer between 1993 and 2007. In total, 3,047 deaths (1,570 breast cancer-specific) were observed with a mean (SD) follow-up of 8.3 (3.5) years. Cox-proportional hazards regression models were fit to data to estimate hazards ratios (HR) and 95% confidence intervals (CI) for overall and breast cancer-specific mortality. Compared with non-Latina Whites, the HR of breast cancer-specific mortality was 1.13 (95% CI, 0.97-1.33) for African Americans, 0.84 (95% CI, 0.70-1.00) for Latinas, and 0.60 (95% CI, 0.37-0.97) for Asian Americans after adjustment for age, tumor characteristics, and select lifestyle factors. The CBCSC represents a large and racially/ethnically diverse cohort of breast cancer patients from California. This cohort will enable analyses to jointly consider a variety of clinical, lifestyle, and contextual factors in attempting to explain the long-standing disparities in breast cancer outcomes.

How Do Differences in Treatment Impact Racial and Ethnic Disparities in Acute Myeloid Leukemia?

“…In agreement with studies in other cancer types, we demonstrate that survival disparities attenuate toward null for black patients when appropriate treatment is delivered (12,18,33). Our study also agrees with previous evaluations that demonstrate no survival disparities for Hispanics after adjustment for age (34)(35)(36), and with literature that show improved survival associated with API race/ethnicity in other types of cancers (29,37). Despite similarities to other studies, our study is novel because it is one of the first to evaluate differences in treatment and the effect on disparities in AML survival using population-based data (23).…”

Use of and Mortality After Bilateral Mastectomy Compared With Other Surgical Treatments for Breast Cancer in California, 1998-2011

“…However, prior studies enriched for clinical data, including our own within the Kaiser Permanente Northern California health care system, reported treatment-limiting comorbidities (for example, diabetes and myocardial infarction) and reduced treatment intensity among the same racial/ethnicminority, low SES patients who most frequently under went unilateral mastectomy in our current study. 28–30 In addition to signifying unmeasured poor prognostic factors, 21,22 unilateral mastectomy might correlate with subtle disparities in effective access (for example, diabetic neuropathy that limits chemotherapy dosing; lack of transportation to the postsurgical radiation treatments required for breast conservation) that we could not identify using registry data and that may mediate higher mortality. By contrast, patterns of bilateral mastectomy use suggest that affluent non-Hispanic white women, women of high SES, or both seek more aggressive preventive care, consistent with reported associations between greater use of expensive diagnostic tests (such as breast MRI and genetic testing) and bilateral mastectomy within this patient subgroup.…”

Diabetes and Other Comorbidities in Breast Cancer Survival by Race/Ethnicity: The California Breast Cancer Survivorship Consortium (CBCSC)

“…This analysis included five studies from the CBCSC, which was established in 2011 to better understand racial/ethnic disparities in survival (5). They include three population-based case-control studies of breast cancer [the Asian American Breast Cancer Study (AABCS) (6); the Women’s Contraceptive and Reproductive Experiences study (CARE) (7); and the San Francisco Bay Area Breast Cancer Study (SFBCS) (8)], one breast cancer survivor cohort [the Life after Cancer Epidemiology (LACE) Study (9)], and one cohort study [the California Teachers Study (CTS) (10)].…”

“…To better understand the association of specific comorbidities with overall mortality and breast cancer-specific mortality by race/ethnicity, we analyzed data from the California Breast Cancer Survivorship Consortium (CBCSC) (5). We considered duration and treatment of comorbidities, as well as stage at diagnosis and treatment for breast cancer, to explore reasons for the potential adverse effects of comorbidities on survival.…”