Risk Prediction Models for Colorectal Cancer: A Systematic Review

Juliet A Usher-Smith, Fiona M Walter, Jon D Emery, Aung K Win, Simon J Griffin

Colorectal cancer (CRC) is the second leading cause of cancer-related death in Europe and the United States. Survival is strongly related to stage at diagnosis and population-based screening reduces CRC incidence and mortality. Stratifying the population by risk offers the potential of improving the efficiency of screening. In this systematic review we searched Medline, EMBASE and the Cochrane Library for primary research studies reporting or validating models to predict future risk of primary CRC for asymptomatic individuals. 12,808 papers were identified from the literature search and nine through citation searching. 52 risk models were included. Where reported (n=37), half the models had acceptable-to-good discrimination (c-statistic>0.7) in the derivation sample. Calibration was less commonly assessed (n=21), but overall acceptable. In external validation studies, 10 models showed acceptable discrimination (c-statistic 0.71-0.78). These include two with only three variables (age, gender and BMI; age, gender and family history of CRC). A small number of prediction models developed from case-control studies of genetic biomarkers also show some promise but require further external validation using population-based samples. Further research should focus on the feasibility and impact of incorporating such models into stratified screening programmes.