CRC Screening: Is It Worthwhile in Younger Adults?

Although current guidelines recommend screening for colorectal cancer (CRC) in average-risk individual starting at age 50 [1], more than 10 % of CRC is diagnosed prior to this age [2]. Furthermore, while the rates for older individuals have decreased, the rates for younger adults may be increasing [2]. Current guidelines recommend that individuals with a family history of CRC or a genetic syndrome should be screened at an age younger than 50 years, preferentially with colonoscopy [1]. In 2009, the American College of Gastroenterology (ACG) recommended colonoscopic screening of African-Americans starting at age 45 [1]. Can other groups of adults who may be at risk of CRC at an early age be identified? In the current issue of Digestive Diseases and Sciences, Jung et al. [3] describe a strategy designed to identify high-risk individuals\50 years old who might benefit from screening colonoscopy and thus reduce the substantial burden of colorectal cancer in this age group. Jung et al. report a cross-sectional analysis of 27,894 Korean adults who underwent an initial colonoscopy for preventative health care. The investigators collected data that included age, sex, height, weight, medications, family history of colorectal neoplasia, smoking exposure, alcohol intake, physical activity, self-reported comprehensive medical and surgical history, and blood pressure measurements. Laboratory data collected included hepatic sonographic data, serum concentrations of triglyceride, cholesterol, and glucose in addition to screening colonoscopy reports. Using these data, the authors stratified the participants by risk factors including sex and age. The investigators then calculated the number needed to screen (NNS) to identify one adult with advanced colorectal neoplasm for each group. The NNS was calculated as the inverse of the prevalence of advanced lesions for each group. Thus, a group with a lower NNS might derive greater benefit from screening colonoscopy than a group with a higher NNS. They compared the NNS in men, stratified into age groups under 50 years as well as varying risk exposures, to those of a low-risk group of women 50 years and older with no known risk factors. The investigators observed that the only group with a lower NNS than the control group of women over age of 50 years (26.4; 95 % CI 19.0–43.5) was the cohort of men 45–49 years old who had all of the risk factors considered by the authors: smoking, metabolic syndrome, obesity, and fatty liver disease (18.4; 95 % CI 12.6–34.1, range 16.9–22.9). Thus, they concluded that there was no benefit to screening high-risk individuals\ 45 years old. Do these data suggest that the effort to find a high-risk group in young adults may be futile? There are many strong points in the current study, which help to support its findings. The major strength is the sample size, which included over 25,000 individuals younger than 50 years, a group that has not been included in most of the previously published screening studies. Furthermore, the exclusion of adults with a family history of CRC is also important since these individuals are The contents of this work do not represent the views of the Department of Veterans Affairs or the United States Government