Study Identifies Geographic Hot Spots With the Highest Colorectal Cancer Death Rates

Key Points

  • Gains have been made in the overall reduction in the death rates of colorectal cancer in the United States.
  • Three geographic 'hot spots' continue to have elevated death rates from colorectal cancer.
  • Compared with non–hot spot areas of the country during 2009 to 2011, colorectal cancer death rates were 40% higher in the lower Mississippi Delta and 18% and 9% higher, respectively, in West Central Appalachia and Eastern Virginia/North Carolina.
  • The introduction of coordinated, targeted, community-based colorectal cancer screening programs in these high-risk areas could be successful in reducing colorectal cancer disparities. 

Gains have been made in the overall reduction in the death rates of colorectal cancer in the United States. A new study by Siegel et al has identified three distinct geographic hot spots where colorectal cancer death rates remain elevated over other parts of the country. These hot spots were found in the lower Mississippi Delta, followed by West Central Appalachia and Eastern Virginia/North Carolina. According to the study, the findings warrant prioritized colorectal cancer screening intervention in these areas. The study is published in Cancer Epidemiology, Biomarkers & Prevention.

Study Methodology

The researchers analyzed colorectal cancer death data from 1970 through 2011 for all counties in the United States using SEER*Stat software. SEER*Stat is a product of the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) Program. They used a geospatial software tool to identify colorectal cancer hot spots (spatial clusters of counties with high rates) based on county-level mortality data from SEER. Hot spots were compared with the remaining aggregated counties (non–hot spot United States) by plotting trends from 1970 to 2011 and calculating rate ratios. Trends were quantified using joinpoint regression.

Study Results

Using this spatial mapping, the researchers identified three distinct hot spots where colorectal cancer death rates are elevated. The highest rates were in the largest hot spot, which encompassed 94 counties in the lower Mississippi Delta and included Arkansas (17), Illinois (16), Kentucky (3), Louisiana (6), Mississippi (27), Missouri (15), and Tennessee (10). During 2009 to 2011, rates in those counties were 40% higher than the non–hot spot United States (rate ratio [RR] = 1.40; 95% confidence interval [CI] = 1.341.46), despite being 18% lower during 1970 to 1972 (RR = 0.82; 95% CI = 0.780.86). The elevated risk was similar in blacks and whites.

Notably, rates among black men in the Delta increased steadily by 3.5% per year from 1970 to 1990 and have since remained unchanged. Rates in hot spots in West Central Appalachia and Eastern Virginia/North Carolina were 18% and 9% higher, respectively, than the non–hot spot United States during 2009 to 2011.

Reducing Cancer Deaths Through Screening Programs

“Cancer prevention through lifestyle modification is the preferable mechanism for decreasing cancer occurrence; however, effecting change to reduce obesity and increase physical activity is extremely difficult. Moreover, the fruits of these efforts are not born at the population level for many years. Promoting and improving access to screening through patient navigation and outreach programs offers a more immediate return on investment. The state of Delaware effectively eliminated colorectal cancer disparities in less than a decade by implementing comprehensive statewide colorectal cancer screening. The rapid introduction of coordinated, targeted, community-based screening programs in these high-risk areas could be similarly successful,” concluded the study authors.

Rebecca L. Siegel, MPH, of the American Cancer Society, is the corresponding author of this study.

Funding for this study was provided by the American Cancer Society. The study authors reported no conflicts of interest.

The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.


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