Concerted efforts to prevent or detect colorectal cancer at earlier stages in black patients could improve the worsening black-white disparities uncovered in a recent analysis, according to investigators.

As Anthony S. Robbins, MD, PhD, and fellow researchers from the American Cancer Society (ACS) in Atlanta, Georgia, explain in the Journal of Clinical Oncology, in the United States, white patients with colorectal cancer have experienced earlier and larger reductions in mortality rates since the 1980s than have black patients. The study team examined whether this mortality pattern varies by stage at diagnosis by analyzing information from the nine original regions included in the Incidence-Based Mortality data base of the Surveillance, Epidemiology, and End Results (SEER) program.

Robbins’ group learned that colorectal cancer mortality rates declined for each stage in both blacks and whites from 1985-1987 to 2006-2008. However, at every stage the reductions were smaller for blacks, particularly for distant-stage disease.

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  • For localized stage, mortality rates fell by 30.3% in whites compared with 13.2% in blacks.
  • For regional stage, mortality rates fell by 48.5% in whites compared with 34.0% in blacks.
  • For distant stage, mortality rates fell by 32.6% in whites compared with just 4.6% in blacks.  

In absolute terms, the disparity in distant-stage mortality rates accounted for approximately 60% of the overall black-white mortality disparity.

An accompanying statement from the ACS points out that whereas colorectal cancer mortality rates for blacks were lower than those for whites, the patterns had reversed and diverged that in 2007 the mortality rate for blacks was 44% higher than that for whites. The worsening disparity coincided with the introduction of screening for the disease and improved treatments.

The study authors cite differences in early detection and differences in treatment as reasons for the disparity, noting that blacks have historically been less likely than whites to be screened, and those who are screened often do not have timely follow-up. Studies have also shown that treatment improvements have been disseminated unevenly among the two patient populations: Adjuvant chemotherapy treatment rates among blacks are relatively low compared with those of whites, despite the known survival benefit conferred by this approach.