Hot spots versus other counties
The goal of the study was to identify mortality hot spots specific to men with early-onset CRC and to evaluate disparities while controlling for sex-specific differences. Rogers and colleagues identified counties with high early-onset CRC mortality rates using data from the Centers for Disease Control and Prevention (1999–2017) and linked them to data from the Surveillance, Epidemiology, and End Results (SEER) for men aged 15 to 49 years.
The team identified 232 US counties (7% of the total) as hot spots. The majority (214 of 232, 92%) were located in the South, and the remainder (18 of 232, 8%) were in the Midwest P < .01).
As compared to men living in other counties, those residing in hot-spot counties were more likely to be non-Hispanic blacks (30.82% vs 13.06%), less likely to be Hispanic (1.68% vs 16.65%; P < .01), and more likely to be diagnosed with metastatic disease (stage IV CRC) (2.58% vs 1.94%; P < .01).
Among men who lived in hot spots, CRC survival was poorer than was seen elsewhere (113.76 vs 129.04 months, respectively; P < .001). Among those with early-onset CRC, the risk for CRC-specific death was 24% higher (hazard ratio [HR], 1.24) than for men living outside of the hot-spot counties. However, that figure dropped to 12% after adjustment for county-level smoking (HR, 1.12).
With respect to racial/ethnic differences, non-Hispanic black (HR, 1.31) and Hispanic (HR, 1.12) patients had a 31% and 12% increased risk for CRC-specific death as compared to non-Hispanic white men (HR, 1.01) after adjusting for smoking status.
The authors note that among all determinants, “clinical stage explained the largest proportion of the variance” in early-onset CRC survival for men living in hot spots and other locations combined.
In the hot-spot counties, severe tumor grade was associated with greater CRC-specific mortality risk. Among patients with poorly differentiated tumors (HR, 1.87) and undifferentiated tumors (HR, 2.60), the mortality risk was nearly 2 times and 2.6 times greater, respectively, than those with well-differentiated tumors.
Compared to other counties, hot-spot counties were characterized by demographics that have been linked to poorer health outcomes, such as higher poverty rates (26.57% vs 16.77%), greater prevalence of adult obesity (34.94% vs 25.89%), higher adult smoking rates (23.97% vs 15.44%), higher uninsured rates (20.06% vs 17.91%), and fewer primary care physicians (58.28 vs 75.45 per 100,000 population).
Geographic distribution of CRC
Commenting to Medscape Medical News, Doubeni pointed out that the identified hot spots are similar to previously reported overall CRC hot spots.
“It shows the same patterns of geographic distribution of colorectal cancer in the United States,” he said. “These patterns tend to be associated with areas with high levels of poverty, as is the case with other chronic diseases, and may be related to clustering of risk factors and limited access to care in those areas.”
The research was supported by the National Cancer Institute of the National Institutes of Health, the Huntsman Cancer Foundation, and the Health Studies Fund of the Department of Family and Preventative Medicine at the University of Utah. The authors and Doubeni have disclosed no relevant financial relationships.
This article first appeared on Medscape.com.