Although the racial divide was measurable in every disease stage, investigators said, late-stage disease was reponsible for much of the difference in mortality, accounting for approximately 60% of the overall black-white mortality disparity, according to Dr. Anthony Robbins, PhD, from the American Cancer Society.
Colorectal cancer mortality rates for whites and blacks in the U.S. have been diverging due to earlier and larger mortality reductions among whites, the authors wrote. The study aimed to determine whether this mortality pattern was persistent with regard to disease stage.
The study team used data from the Surveillance, Epidemiology, and End Results (SEER) program to examine changes in stage-specific mortality rates by race.
The results showed that between 1985 and 2008, colorectal cancer mortality decreased for each disease stage in blacks and whites, but the decreases for blacks were smaller in every stage, especially distant-stage disease. For local disease, mortality dropped 30.3% in whites compared with 13.2% in blacks; for regional colorectal cancer, deaths in whites dropped 48.5% versus 34.0% in blacks. And for distant-stage disease, deaths among whites dropped 32.6% versus 4.6% in blacks.
The disparity in distant-stage mortality rates accounted for approximately 60% of the overall black-white mortality disparity, the authors reported. While black-white disparities in colorectal cancer mortality rose at each stage of disease, the disparity in overall mortality was propelled by the large differences in mortality from late-stage disease, they concluded. Concerted efforts to prevent cancer in blacks or find it earlier could improve the worsening black-white disparities, they noted.