A modified colorectal screening score for prediction of advanced neoplasia: A prospective study of 5744 subjects

Abstract

Background and aim: We validated a modified risk algorithm based on the Asia-Pacific Colorectal Screening (APCS) score that included body mass index (BMI) for prediction of advanced neoplasia.

Methods: Among 5744 Chinese asymptomatic screening participants undergoing a colonoscopy in Hong Kong from 2008 to 2012, a random sample of 3829 participants acted as the derivation cohort. The odds ratios for significant risk factors identified by binary logistic regression analysis were used to build a scoring system ranging from 0 to 6, divided into "average risk" (AR): 0; "moderate risk" (MR): 1-2; and "high risk" (HR): 3-6. The other 1915 subjects formed a validation cohort, and the performance of the score was assessed.

Results: The prevalence of advanced neoplasia in the derivation and validation cohorts was 5.4% and 6.0%, respectively (P = 0.395). Old age, male gender, family history of colorectal cancer, smoking, and BMI were significant predictors in multivariate regression analysis. A BMI cut-off at > 23 kg/m² had better predictive capability and lower number needed to screen than that of > 25 kg/m² . Utilizing the score developed, 8.4%, 57.4%, and 34.2% in the validation cohort were categorized as AR, MR, and HR, respectively. The corresponding prevalence of advanced neoplasia was 3.8%, 4.3%, and 9.3%. Subjects in the HR group had 2.48-fold increased prevalence of advanced neoplasia than the AR group. The c-statistics of the modified score had better discriminatory capability than that using predictors of APCS alone (c-statistics = 0.65 vs 0.60).

Conclusions: Incorporating BMI into the predictors of APCS score was found to improve risk prediction of advanced neoplasia and reduce colonoscopy resources.

Keywords: advanced colorectal neoplasia; body mass index; colorectal cancer screening; risk estimation; scoring algorithm.