SCRIPT: an RCT of genomic-based stratified colorectal cancer screening in primary care

Project Summary

Colorectal cancer screening is a highly cost-effective strategy to reduce mortality and morbidity from this disease. Australian guidelines recommend a risk-stratified approach in which those at near average risk use the faecal occult blood test from age 50, and only those at increased risk of colorectal cancer have more intensive screening, commencing at an earlier age and using colonoscopy as the screening test. Despite these guidelines, there are wide variations in practice across Australia with 30-fold differences in the use of colonoscopy depending on where a patient lives.

Approximately one million people at average risk of colorectal cancer are undergoing expensive and invasive colonoscopy resulting in an estimated 80 deaths, 1,400 bleeds and 680 bowel perforations to detect 2,910 cancers. In addition, approximately 400,000 Australians at increased risk of colorectal cancer are not receiving colonoscopy to reduce their risk of colorectal cancer and associated mortality. Risk is currently assessed using only a person’s age and family history but this is inaccurate. We have developed and validated a novel polygenic risk score, currently based on 45 single nucleotide polymorphisms (SNPs), which can assess accurately the future risk of colorectal cancer.  SCRIPT will test the implementation of precision screening using this polygenic risk score in primary care, aiming to:

• Increase faecal occult blood testing in average risk people.
• Reduce inappropriate colonoscopy in average risk people.
• Identify people at increased risk and refer them for appropriate colonoscopy

Publications

• Saya S, McIntosh JG, Winship IM, Milton S, Clendenning M, Kyriakides M, Emery J, et al. Informed choice and attitudes regarding a genomic test to predict risk of colorectal cancer in general practice. Patient Education and Counseling, 2021. doi:10.1016/j.pec.2021.08.008