The use of a risk assessment and decision support tool (CRISP) compared with usual care in general practice to increase risk-stratified colorectal cancer screening: study protocol for a randomised controlled trial

Jenny Walker ,Malcolm Clark,Finlay Macrae,Richard De Abreu Lourenço,Lyndal Trevena,Driss Ait Ouakrim,Louisa Flander,James G Dowty ,George Fishman,Mark A Jenkins ,Fiona M Walter,Patty Chondros,Shakira Milton,Adrian Bickerstaffe,Marie Pirotta,Sibel Saya,Louise Galloway,Ingrid Winship,Jasmeen Oberoi,Jon Emery

doi:10.1186/s13063-018-2764-7

Abstract

BackgroundAustralia and New Zealand have the highest incidence rates of colorectal cancer worldwide. In Australia there is significant unwarranted variation in colorectal cancer screening due to low uptake of the immunochemical faecal occult blood test, poor identification of individuals at increased risk of colorectal cancer, and over-referral of individuals at average risk for colonoscopy. Our pre-trial research has developed a novel Colorectal cancer RISk Prediction (CRISP) tool, which could be used to implement precision screening in primary care. This paper describes the protocol for a phase II multi-site individually randomised controlled trial of the CRISP tool in primary care.MethodsThis trial aims to test whether a standardised consultation using the CRISP tool in general practice (the CRISP intervention) increases risk-appropriate colorectal cancer screening compared to control participants who receive standardised information on cancer prevention. Patients between 50 and 74 years old, attending an appointment with their general practitioner for any reason, will be invited into the trial. A total of 732 participants will be randomised to intervention or control arms using a computer-generated allocation sequence stratified by general practice. The primary outcome (risk-appropriate screening at 12 months) will be measured using baseline data for colorectal cancer risk and objective health service data to measure screening behaviour. Secondary outcomes will include participant cancer risk perception, anxiety, cancer worry, screening intentions and health service utilisation measured at 1, 6 and 12 months post randomisation.DiscussionThis trial tests a systematic approach to implementing risk-stratified colorectal cancer screening in primary care, based on an individual’s absolute risk, using a state-of-the-art risk assessment tool. Trial results will be reported in 2020.Trial registrationAustralian and New Zealand Clinical Trial Registry, ACTRN12616001573448p. Registered on 14 November 2016.

Highlights

Australia and New Zealand have the highest incidence rates of colorectal cancer worldwide
The primary objective of the cancer RISk Prediction (CRISP) trial is to determine whether the effect of a standardised consultation using the CRISP risk assessment tool in general practice, compared with the provision of generic cancer prevention information, increases the proportion of participants who undergo risk-appropriate colorectal cancer screening; that is, completion of the right screening test based on an individual’s absolute risk of colorectal cancer and the Australian Guidelines at the time [10]
Given the low estimated rates of risk-appropriate screening, we considered several scenarios where the risk-appropriate screening at 12 months increased in the control arm (Table 1) and selected a more conservative sample size that was achievable and practical

Summary

Introduction

Australia and New Zealand have the highest incidence rates of colorectal cancer worldwide. In Australia there is significant unwarranted variation in colorectal cancer screening due to low uptake of the immunochemical faecal occult blood test, poor identification of individuals at increased risk of colorectal cancer, and over-referral of individuals at average risk for colonoscopy. There is a wide geographical variation in incidence of colorectal cancer worldwide, with the highest rates in Australia and New Zealand and the lowest in Western Africa [1]. Australian guidelines recommend screening with an iFOBT for people at “average and slightly increased risk” and colonoscopy for those at “increased risk” These guidelines rely only on age and family history and are limited in their ability to detect individuals at high risk [10]. Risk prediction models can provide estimates of colorectal cancer risk so that more expensive and higher risk preventive strategies, such as colonoscopy, can be targeted at those most likely to benefit [14, 15]

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