Although the overall incidence of colorectal cancer has declined in the United States, the rate at which the disease is diagnosed in young adults has increased significantly, according to results of a SEER analysis.
Christina E. Bailey, MD, MSCI, surgical oncology fellow at The University of Texas MD Anderson Cancer Center, and colleagues used the SEER colorectal cancer registry to identify 393,241 patients who underwent colon or rectal cancer surgery between 1975 and 2010.
Overall, the age-adjusted incidence of colorectal cancer decreased 0.92% (95% CI, –1.14 to –.7) during the study period. Data indicated colorectal cancer incidence declined in men (annual percentage change [ACP], –1.03; 95% CI, –1.3 to –0.76) and women (ACP, –0.91; 95% CI, –1.09 to –0.73).
Researchers also noted a 1% (95% CI, –1.23 to –0.77) decline in colorectal cancer incidence among white individuals, a 0.17% (95% CI, –0.43 to 0.09) decline among black individuals, and a 0.53% (95% CI, –0.75 to –0.31) decline among individuals of other or unknown races/ethnicities.
Data stratified by age indicated the largest declines in colorectal cancer incidence occurred among those aged 75 years or older (ACP, –1.15; 95% CI, –1.47 to –0.87) and those aged 50 to 74 years (ACP, –0.97; 95% CI, –1.17 to –0.76).
However, colorectal cancer incidence increased 1.99% (95% CI, 1.48-2.51) among those aged 20 to 34 years, and incidence increased 0.41% (95% CI, 0.14-0.69) among those aged 35 to 49 years.
These trends persisted when researchers stratified data by age and disease stage. Patients aged 20 to 34 years demonstrated increased incidence of local, regional and distant colon and rectal cancers.
Using these data, researchers estimated colon cancer incidence among individuals aged 20 to 34 years will increase 37.8% by 2020 and 90% by 2030. They predicted patients aged older than 50 years will demonstrate a 23.2% decline in colon cancer incidence by 2020 and a 41.1% decline by 2030.
Researchers also estimated rectal cancer incidence among those aged 20 to 34 years will increase 49.7% by 2020 and 124.2% by 2030, whereas incidence among those aged 50 years and older will decrease 23.2% by 2020 and 41% by 2030.
Kiran K. Turaga
“The increasing incidence of colorectal cancer among young adults is concerning and highlights the need to investigate potential causes and external influences, such as lack of screening and behavioral factors,” Bailey and colleagues wrote.
Despite the increased incidence in younger adults, health care professionals should be cautious about dramatically increasing colorectal cancer screening in this population, Kiran K. Turaga, MD, MPH, assistant professor of surgery at the Medical College of Wisconsin, wrote in an invited commentary.
“While it is attractive to suggest that all adults should obtain a colonoscopy, especially given the possible durability of cancer risk reduction, it is important to note that the absolute incidence of colorectal cancer in the young adults (aged 20 to 34 years) is 1% of the total colorectal cancer burden and similarly fairly low in the 35- to 49-year-old age group (6.8%),” Turaga wrote. “Hence, widespread application of colonoscopic screening might add significant cost and risk without societal benefit. However, this report should stimulate opportunities for development of better risk-prediction tools that might help us identify these individuals early and initiate better screening/prevention strategies.”
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Disclosure: The study was funded in part by grants from the NIH and NCI. Turaga reports consultant roles with Castle Bioscience and Ethicon. The other researchers report no relevant financial disclosures.