Study Finds Colorectal Cancer Screenings Vary Widely Throughout the United States
A study examining prevalence estimates of colorectal cancer screening at the county level in the United States has found that the country is far behind reaching the goal of screening 80% of adults aged 50 and older for colorectal cancer by 2018, which is supported by the National Colorectal Cancer Roundtable, the American Cancer Society, and the Centers for Disease Control and Prevention (CDC), among others. In fact, the study by Berkowitz et al found wide variations in colorectal screening rates, with a difference in estimated percentages of 40% between the highest and lowest ranking counties for any colorectal cancer test type or for colonoscopy. The study is published in Cancer Epidemiology, Biomarkers & Prevention.
The U.S. Preventive Services Task Force (USPSTF) recommends that adults aged 50 to 75 get routine screening for colorectal cancer, a disease that is preventable through early detection and the removal of precancerous polyps and early-stage cancers.
Study Methodology
The researchers used county data from the CDC’s 2014 Behavioral Risk Factor Surveillance System (BRFSS), linked it to the American Community Survey poverty data, and fitted multilevel logistic regression models. The researchers used information from 251,360 BRFSS respondents aged 50 to 75 and U.S. Census Bureau population estimates for all 3,142 counties in the 50 states and the District of Columbia.
They followed the 2008 USPSTF colorectal cancer screening guideline recommendations to routinely screen average risk adults aged 50 to 75 with 1 of 3 options: fecal occult blood testing (FOBT) within 1 year; sigmoidoscopy within 5 years, with FOBT within 3 years; or colonoscopy within 10 years.
Study Findings
The researchers’ nationwide analysis showed that 67.3% of the adult population aged 50 to 75 was current with colorectal cancer screening. They found screening varied by ethnicity, with 69.2% of non-Hispanic whites current with screening, whereas only 56.8% of Hispanics were current. Colonoscopy was the most popular method of screening, with 63.7% of the adult population undergoing the procedure within 10 years.
Model-based state estimates found substantial variations in current colorectal cancer screening estimates, ranging from the lowest prevalence (58.9%) in Wyoming to the highest (75.0%) in Massachusetts. Model-based county estimates found that the county with the lowest prevalence in colorectal screening was in Alaska (40.1%), and the county with the highest prevalence was in Florida (79.8%).
“State estimates mask county variations. However, both state and county estimates indicate that the country is far behind the “80% by 2018” target,” concluded the study authors.
“We anticipated county variations of [colorectal cancer] screening rates within the states because we know there are differences between urban and rural areas in adherence to screening recommendations,” said Zahava Berkowitz, MSPH, MSc, a statistician in the National Center for Chronic Disease Prevention and Health Promotion at the CDC and the lead author of this study, in a statement. “However, we were struck by differences of more than 20 percentage points among counties in some states. On a state level, our results identify counties where [colorectal cancer] screening rates are the lowest. These findings can help guide interventions that could increase [colorectal cancer] screening rates in these areas.”
Ms. Berkowitz is the corresponding author of this study.
No funds or grants were involved in this study. The study authors declared no conflicts of interest.
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