Racial disparities in stage-specific colorectal cancer mortality rates from 1985 to 2008

Abstract

Purpose: Since the early 1980s, colorectal cancer (CRC) mortality rates for whites and blacks in the United States have been diverging as a result of earlier and larger reductions in death rates for whites. We examined whether this mortality pattern varies by stage at diagnosis.

Methods: The Incidence-Based Mortality database of the Surveillance, Epidemiology, and End Results (SEER) Program was used to examine data from the nine original SEER regions. Our main outcome measures were changes in stage-specific mortality rates by race.

Results: From 1985 to 1987 to 2006 to 2008, CRC mortality rates decreased for each stage in both blacks and whites, but for every stage, the decreases were smaller for blacks, particularly for distant-stage disease. For localized stage, mortality rates decreased 30.3% in whites compared with 13.2% in blacks; for regional stage, declines were 48.5% in whites compared with 34.0% in blacks; and for distant stage, declines were 32.6% in whites compared with 4.6% in blacks. As a result, the black-white rate ratios increased from 1.17 (95% CI, 0.98 to 1.39) to 1.41 (95% CI, 1.21 to 1.63) for localized disease, from 1.03 (95% CI, 0.93 to 1.14) to 1.30 (95% CI, 1.17 to 1.44) for regional disease, and from 1.21 (95% CI, 1.10 to 1.34) to 1.72 (95% CI, 1.58 to 1.86) for distant-stage disease. In absolute terms, the disparity in distant-stage mortality rates accounted for approximately 60% of the overall black-white mortality disparity.

Conclusion: The black-white disparities in CRC mortality increased for each stage of the disease, but the overall disparity in overall mortality was largely driven by trends for late-stage disease. Concerted efforts to prevent or detect CRC at earlier stages in blacks could improve the worsening black- white disparities.