Disparities between blacks and whites in stage at diagnosis, incidence, and anatomic subsite of colorectal cancer

Background: A disparity in colorectal cancer (CRC) incidence and mortality has been reported for black men and women in the United States. Objective: To determine the magnitude and direction of temporal change in black/white disparity, by anatomic subsites of the colon and rectum. Design: Population-based, epidemiologic study. Setting: Pennsylvania, 1997-2002. Measurements: Black/white ratios of the percentage of cases diagnosed at late stage and of age-adjusted incidence rates, by anatomic subsite, for four 3-year time periods. Results: In 2000-2002, 54.6% of CRC cases among blacks were diagnosed at late stage, compared with 51.3% among whites. The percentage of cases in the cecum, transverse colon, splenic flexure, descending colon, sigmoid colon, rectum, and recto-sigmoid diagnosed at a late stage was larger among blacks than among whites. The disparity in the percentage of cases diagnosed at a late stage in the colon and rectum, transverse colon, and descending colon increased during the study period (P<.05). In 2000-2002, incidence was greater among blacks (64.1/100,000) than among whites (59.8/100,000). Incidence for segments of the proximal colon tended to be higher among blacks than among whites. The disparity in the incidence in the transverse colon increased during the study period (P=.021), while the increase in the disparity in the appendix approached statistical significance (P=.051). Limitations: The effect of race may have been confounded by unavailable data, including socioeconomic position. Conclusions: The black/white disparity in the percentage of cases diagnosed at late stage increased during the study period. The disparity in the percentage of cases diagnosed at a late stage and incidence for the transverse colon also increased. Efforts to increase screening for CRC, especially among blacks, should be enhanced.