'Why don't I need a colonoscopy?' A novel approach to communicating risks and benefits of colorectal cancer screening.

Background and Objectives: There is significant growth in demand for colonoscopies, with over 700,000 performed in Australia in 2012-13. For every one million Australians aged 50 years and older, 80,000 people at average risk of colorectal cancer are being over-screened with colonoscopy, and 29,000 people at increased risk are not having the colonoscopy they need.
Method: Using monitoring data from the Australian National Bowel Cancer Screening Program and published data on colonoscopic screening, we have developed expected frequency trees (EFTs) to demonstrate projected outcomes of different colorectal cancer screening options for participants at different levels of colorectal cancer risk in Australia.
Results: The EFTs highlight the overall balance in favour of faecal occult blood screening for those at average risk in terms of fewer deaths and complications.
Discussion: This novel method of risk communication can be used to promote appropriate patient choice of colorectal cancer screening modality and potentially reduce the number of referrals for colonoscopy in patients who are not at increased risk of colorectal cancer.