Abstract PC01-01: Colorectal cancer screening for African Americans: Should we be screening at an earlier age? The Pro side
Authors: Carethers John M. 
Published: May 2015

Colorectal cancer is the second leading cause of cancer mortality in the United States, and there are seven tests recommended for its screening to help detect cancer and/or its precursors at an early stage. Major risk factors for colorectal cancer are age, family history, and race. Surveillance, Epidemiology, and End Results (SEER) data consistently show that in the United States that Blacks have the highest incidence of and highest mortality from colorectal cancer, compared to Whites, Native Americans, Hispanic Americans, and Asian Americans. Blacks, when compared to Whites, tend to present at advance stages of colorectal cancer, and have poorer survival at all stages. There are a number of theories and potentially contributing factors to cause this disparity, including socio-economic, insurance, and education differences, access to medical care, the use of colorectal cancer screening methods, types of diet, obesity and physical activity, use of tobacco products, use of NSAIDs and hormone replacement therapy, but it is not clear if one or all factors are contributing and/or are relevant. Some studies point towards health care utilization as the major contributing factor for disparity. Additionally, there is strong evidence that Blacks have an anatomical shift of polyps and cancer to the right colon when compared to Whites. This is important as colonoscopic screening does not reduce mortality to the same degree when cancers are in the right side of the colon when compared to left-sided colon cancers. The proportion of Blacks presenting with colorectal cancer below the age of 50 when screening is recommended is 10.6%, compared to 5.5% for Whites. This rate approximates 5.5% for Blacks at age 45 years. The American College of Gastroenterology, the American College of Physicians, and the Institute for Clinical Systems Improvement have all recommended earlier ages (40 or 45 years) to begin screening Blacks for colorectal cancer in the United States, although other organizations have yet to make this recommendation.

A general approach to any cancer screening involves (a) a sensitive and specific test, (b) acceptable to asymptomatic persons, (c) reduce morbidity and mortality, and (d) be cost-effective and affordable to society. Most of the seven tests recommended for colorectal cancer screening meet these general criteria. There are modifications to colorectal cancer screening based on higher risk populations, such as those with potential familial inheritance of cancer and those with a history of inflammatory bowel disease. The rationale is that these populations develop colorectal cancer earlier, and that by screening them earlier will find cancers or their precursors at early stages. Based on objective data, colonoscopic screening should be the preferred approach for Blacks due to the higher right-sided colon prevalence for polyps and cancers. And, as for inflammatory bowel disease and potential hereditary predisposition or based on family history, the time for screening Blacks should be at an earlier age due to higher prevalence and mortality from colorectal cancer. Indeed, the cost-effectiveness for screening Blacks with colonoscopy is much greater than Whites due to the higher rates of the disease.

Citation Format: John M. Carethers. Colorectal cancer screening for African Americans: Should we be screening at an earlier age? The Pro side. [abstract]. In: Proceedings of the Sixth AACR Conference: The Science of Cancer Health Disparities; Dec 6–9, 2013; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2014;23(11 Suppl):Abstract nr PC01-01. doi:10.1158/1538-7755.DISP13-PC01-01