Lack of reduction in racial disparities in cancer-specific mortality over a 20-year period

Abstract

Background: To the authors' knowledge, it remains unknown whether race-based differences in cancer outcomes have changed with time. In the current study, the authors assessed whether racial disparities in cancer-specific mortality have improved over the last 20 years.

Methods: The Surveillance, Epidemiology, and End Results program was used to identify 2,713,474 patients diagnosed between 1988 and 2007 with either lung, breast, prostate, or colorectal cancer (the leading 3 causes of cancer-related mortality among each sex). After exclusions, 1,001,978 patients remained eligible for analysis. The impact of race on cancer-specific mortality was assessed using the regression model of Fine and Gray; an interaction model evaluated trends over time.

Results: African Americans presented with a more advanced stage of disease (P < .001) and underwent definitive therapy less often (P < .001) than whites. After adjustment for demographics and year of diagnosis, African Americans were found to have higher estimates of cancer-specific mortality than whites for all cancers combined (hazards ratio, 1.28; 95% confidence interval, 1.26-1.30 [P < .001]) and within each individual cancer (each P < .05). These differences did not change significantly between 1988 through 1997 and 1998 through 2007, except among patients with breast cancer, in whom survival disparities increased. These findings remained significant after adjustment for stage of disease at presentation and receipt of definitive therapy (hazards ratio for breast cancer mortality in African Americans vs whites: 1.37 from 1988-1997 and 1.53 from 1998-2007; P for interaction, < .001).

Conclusions: The survival gap for African Americans has not closed over time. Race-based differences in outcome persist independent of stage of disease and treatment, suggesting that additional strategies beyond screening and improving access to care, such as further research into tumor biologies disproportionately affecting African Americans, are needed to improve survival for African American patients with cancer.

Keywords: African American; Asian American; Hispanic; black; cancer; metastatic; mortality; radiation; surgery; white.