JMIR Publications

ABSTRACT

Background:

Incidence and mortality from colorectal cancer (CRC) can be effectively reduced by screening with faecal immunochemical test (FIT) or colonoscopy. Individual risk to develop CRC within 15 years varies from <1% to >15% among people aged 50 to 75. Communicating personalized CRC risk score and appropriate screening recommendations could improve the risk-benefit balance of screening tests allocation and optimize the use of limited colonoscopy resources. However, significant uncertainty exists regarding the feasibility and efficacy of risk-based screening.

Objective:

We aim to study the effect of communicating individual risk of developing CRC and a risk-based recommendation of FIT or colonoscopy on participants’ choice of screening test. We will also assess the feasibility of a larger clinical trial designed to evaluate the impact of personalized screening on clinical outcomes.

Methods:

We will perform a pilot randomized controlled trial among 880 residents aged between 50 and 69 years eligible to participate in the organized screening program of the Canton of Vaud, Switzerland. Participants will be recruited by mail by the Vaud Cancer Screening Program. Primary and secondary outcomes will be self-assessed through questionnaires. The personalized risk score will be calculated using a questionnaire and the open source QCancer calculator that was developed and validated in the UK. Participants will be stratified into low (<3%), moderate (3-5%) and high (≥6%) risk groups according to their 15-year CRC risk, and randomized within each risk stratum. The intervention group participants will receive a newly designed brochure with their personalized risk score and appropriate screening recommendations. The control group will receive the usual brochure of the Vaud CRC screening program. Our primary outcome is appropriate screening uptake six months after the intervention using a short self-administered questionnaire. Screening will be defined as appropriate if high-risk participants undertake colonoscopy and low-risk participants undertake FIT. We will also measure acceptability of the risk score and the screening recommendations, psychological factors influencing screening behaviour using a self-administrated questionnaire and semi-structured interviews, as well as feasibility of a full-scale RCT.

Results:

We expect that a total sample of 880 individuals will allow us to detect a difference of 10% (level alpha=5%) between groups. The main outcome will be analyzed using a 2-tailed chi-squared test. We expect that appropriate screening uptake will be greater in the intervention group. No difference in overall screening uptake is expected.

Conclusions:

We will test the impact of personalized risk information and screening recommendations on the choice of screening tests in an organized screening program. This study should advance our understanding of the feasibility of large-scale, risk-based CRC screening. Our results may give insights into optimization of CRC screening by offering screening options with a better risk-benefit balance and optimize the use of resources. Clinical Trial: Clinicaltrials.gov NCT05357508