Colon Cancer Hotspots: More Similar to Romania and Russia than to Rest of the U.S.

The large drop in colorectal cancer death rates in the United States is one of the real success stories in cancer. But while the risk of death from colorectal cancer is at a historical low for most Americans, progress has lagged among residents of the Lower Mississippi Delta and other rural areas; areas identified by American Cancer Society researchers as ‘hotspots’ that warrant intervention.

For their study, Rebecca Siegel, MPH and colleagues looked at colorectal cancer death rates from 1970 through 2011 for all counties in the United States using data from the National Center for Health Statistics.

They found the age-standardized colorectal cancer death rate decreased from 29.2 per 100,000 Americans in 1970 to 15.1 per 100,000 in 2011. Before 1990, colorectal cancer death rates were highest in the northeast and mid-central United States and lowest in the South. However, by the 2000s, rates were generally homogeneous across the country with the exception of three distinct spatial clusters, or hotspots.

These hotspots were located in the Lower Mississippi Delta, west central Appalachia, and eastern North Carolina/Virginia. They comprised 238 counties in 12 states. “The patterns in colorectal cancer death rates in these high-risk areas are more similar to those in economically transitioning countries with limited health care resources, such as Romania, Russia, and Mexico, than to those in the United States,” the researchers write.

Spatial mapping identified three distinct hotspots in the United States where colorectal cancer death rates were elevated.

The authors point to several factors likely to be playing a role in fueling these hotspots: lower rates of screening, which has played a major role in reducing colorectal cancer mortality; economically disadvantaged areas are known to have higher colorectal cancer death rates due to both higher incidence rates and poorer disease outcomes; higher rates of obesity; an unhealthy diet high in soft drinks, red meat, and salty snacks; and lack of physical activity, which protects against colorectal cancer.

In concluding, the researchers point to the state of Delaware, which “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.”