While the incidence of colorectal cancer in people 50 years or older has declined, the incidence among people 20 to 49 years has increased, according to a report published online recently by JAMA Surgery.¹ From 1998 through 2006, the incidence of colorectal cancer declined 3% per year in men and 2.4% in women, a decrease largely attributed to an increase in screening, which is recommended for all adults over 50 years old. However, incidence of colorectal cancer in adults younger than 50, for whom screening is not recommended, appears to be increasing and those patients are more likely to present with advanced disease, according to background information in the study.

SEER Colorectal Cancer Registry

Researcher Christina E. Bailey, MD, MSCI, a surgical oncology fellow at The University of Texas MD Anderson Cancer Center, Houston, and her coauthors analyzed age disparities in trends in colorectal cancer incidence in the United States. The authors used data from the Surveillance, Epidemiology and End Results (SEER) colorectal cancer registry. Data were obtained from the National Cancer Institute’s SEER registry for all patients diagnosed with colon or rectal cancer from 1975 through 2010 (N = 393,241).

The study results indicate that overall, the colorectal cancer incidence rate declined 0.92% between 1975 and 2010. The colorectal cancer incidence rates declined overall by 1.03% in men and 0.91% in women. The most pronounced decline was 1.15% in patients 75 years or older, while the rate for patients 50 to 74 years dropped 0.97%. However the colorectal cancer incidence rates increased for patients 20 to 49 years old, with the biggest increase of 1.99% in patients 20 to 34 years old. The rate increased 0.41% in patients 35 to 49 years old.

Trend Toward Increasing Incidence in Younger People

The authors estimate that by 2020 and 2030, the incidence rate of colon cancer will increase by 37.8% and 90%, respectively, for patients 20 to 34 years old, while decreasing by 23.2% and 41.1%, respectively, for patients older than 50 years.

By 2020 and 2030, the incidence rates for rectosigmoid and rectal cancers are expected to increase by 49.7% and 124.2%, respectively, for patients 20 to 34 years old, while decreasing 23.2% and 41%, respectively, for patients older than 50 years, according to the results.

“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,” the authors concluded.

Colorectal cancer is the third most common malignancy among both men and women, with an estimated 142,820 new cases and an estimated 50,830 deaths in the United States in 2013.

“While our study observations are limited to colorectal cancer, similar concerns are being raised about breast cancer, as we see incidence increasing among younger women,” said principal investigator George J. Chang, MD, MS, Associate Professor, Departments of Surgical Oncology and Health Services Research, at MD Anderson Cancer Center. “Identifying these patterns is a crucial first step toward initiating important shifts in cancer ­prevention.” ■

Reference

1. Bailey CE, Hu CY, You N, et al: Increase in incidence of colorectal cancer in young adults, rates expected to rise. JAMA Surg. November 5, 2014 (early release online).