Lifestyle Changes and Colorectal Neoplasia Risk During Colonoscopy Surveillance: A Stage 1 Registered Report.

[BACKGROUND] The development of colorectal neoplasia (precancerous lesions and colorectal cancer [CRC]) is linked to both non-modifiable and modifiable risk factors among average CRC risk populations. However, no longitudinal studies have assessed non-modifiable and modifiable risk factors and colorectal neoplasia risk among above-average risk CRC populations that require regular surveillance colonoscopy. Therefore, this research project will establish a large-scale colonoscopy surveillance dataset that collects lifestyle and clinical data at multiple time points to assess the effect of lifestyle changes over time on colorectal neoplasia risk.

[METHODS] A prospective follow-up study will be conducted among patients who are enrolled in a South Australian colonoscopy surveillance programme. About 21,000 patients will be invited to take self-reported surveys. Existing programme clinical data will be combined with annual prospectively collected survey data for three consecutive years. Surveys will capture changes in lifestyle patterns over time, including diet, physical activity, sleep quality, smoking habits, and alcohol consumption data at several time points using validated tools. Linear and generalised linear mixed effects models and joint modelling will be used to model continuous, categorical, and a combination of longitudinal and survival data on lifestyle scores and colorectal neoplasia risk, respectively.

[CONCLUSIONS] This study will be the first to investigate how changes in lifestyle patterns over time influence the development of early precancerous lesions and invasive cancer. Inclusion of high-risk lifestyle factors when recommending colonoscopy surveillance intervals could provide an improved, personalised CRC prevention strategy to reduce colorectal neoplasia incidence and colonoscopy workload in those at above-average risk of developing CRC.