Clinical Scoring System May Help Identify Appropriate Colorectal Cancer Screening Methods
Researchers investigating a risk index for colorectal cancer and advanced precancerous polyps among average-risk people have found that patients classified as low risk had fewer advanced adenomas than patients classified as high risk. Their findings suggest that those at low risk for colorectal cancer may benefit from a less-invasive test than colonoscopy, such as sigmoidoscopy or occult blood test, and that colonoscopy should be targeted toward higher-risk individuals.
The ability to estimate accurately and reliably and stratify risk for colorectal cancer and advanced precancerous polyps among persons currently classified as average risk could help tailor screening and improve the overall uptake and efficiency of screening. The study by Imperiale et al was published in Annals of Internal Medicine.
Study Methodology
The study was conducted at the Indiana University Medical Center in Indianapolis. Between 2004 and 2011, the researchers recruited 4,460 patients aged 50 to 80 scheduled to undergo their first screening colonoscopy. Individuals with inflammatory bowel disease, a high-risk family history of polyposis or nonpolyposis colorectal cancer syndrome, or a history of polyps that required follow-up colonoscopy were excluded from the study.
Before having a colonoscopy, participants were asked to complete a questionnaire about risk factors, including family history of colorectal cancer; sociodemographic factors; and lifestyle factors, including smoking history. Study participants were also asked to record their height, weight, and waist and hip circumference.
The goal of the analysis was to determine model performance using five factors that are most commonly associated with colorectal neoplasia, including age, sex, cigarette smoking, body fat, and a family history of colorectal cancer. Derivation and validation of a risk index were based on points from regression coefficients for the five factors. On the basis of the risk for (or prevalence of) advanced neoplasia and the risk score, the researchers indentified four risk groups—very low, low, intermediate, and high—in the study.
Study Findings
Among 2,993 persons in the derivation set, the prevalence of advanced neoplasia was 9.4%. Risks for advanced neoplasia in persons at very low, low, intermediate, and high risk were 1.92% (95% confidence interval [CI] = 0.63%–4.43%), 4.88% (95% CI = 3.79%–6.18%), 9.93% (95% CI = 8.09%–12.0%), and 24.9% (95% CI = 21.1%–29.1%), respectively (P <.001). Sigmoidoscopy to the descending colon in the low-risk groups would have detected 51 of 70 (73% [95% CI = 61%–83%]) advanced neoplasms.
Among 1,467 persons in the validation set, corresponding risks for advanced neoplasia were 1.65% (95% CI = 0.20%–5.84%), 3.31% (95% CI = 2.08%–4.97%), 10.9% (95% CI = 8.26%–14.1%), and 22.3% (95% CI = 16.9%–28.5%), respectively (P <.001). Sigmoidoscopy would have detected 21 of 24 (87.5% [95% CI = 68%–97%]) advanced neoplasms.
Promising Decision-Making Tool
“This 5-variable risk index may help decision-making about colorectal cancer screening for persons currently considered to be at average risk, for whom several test options are equally strongly recommended. The index identified both lower-risk groups that may be screened with strategies other than colonoscopy and a higher-risk group for which colonoscopy may be preferable in terms of yield and efficiency. If this index is further validated externally in independent cohorts, it could increase the uptake and efficiency of colorectal cancer screening in the United States,” concluded the study authors.
Thomas F. Imperiale, MD, of Indiana University, is the corresponding author of this study.
Funding for this study was provided by the National Cancer Institute, the Walther Cancer Institute, Indiana University Simon Cancer Center, and Indiana Clinical and Translational Sciences Institute.
Dr. Imperiale reported grants from the National Cancer Institute, the Walther Cancer Foundation, the Indiana Clinical and Translational Sciences Institute, and the Indiana University Melvin and Bren Simon Cancer Center. The remaining study authors reported no potential conflicts of interest.
The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.
