CARE-CRC: Microbiome Insights and Correlations for Risk and Outcomes in Colorectal Cancer

This study focuses on identifying faecal microbiome biomarkers for CRC across different stages, prognoses, and therapeutic responses, with a particular emphasis on EoCRC. Recruitment will include individuals recently diagnosed with CRC who have not undergone treatment. Faecal samples will be collected at three key time points: Baseline - At diagnosis and study entry. Post-Treatment - After completing each therapeutic regimen, such as neoadjuvant chemotherapy, surgery and/or adjuvant chemotherapy Follow-Up - Three years after diagnosis. The study will also monitor survival rates and disease progression over three years. Primary Objective: To identify and characterise changes in the gut microbiome at different CRC stages. Secondary Objectives: i. Identify faecal microbiome biomarkers associated with CRC overall and stratify findings by age and sex. ii. Compare microbiome profiles and associated clinical and lifestyle data between CRC patients and healthy controls, stratified by age and sex. iii. Identify lifestyle and dietary factors contributing to CRC risk, stratified by age and sex. iv. Validate biomarkers specific to EoCRC. v. Correlate microbiota composition with overall survival. vi. Correlate microbiota composition with disease-free survival. This is a longitudinal observational study targeting individuals aged 40-74 who have been newly diagnosed with CRC and are treatment-naïve Patients with all inclusion criteria and none of the exclusion criteria (detailed in the specific section of this website) will be considered for this study. Using a significance level of 5% and a power of 80%, the required sample size is 80 individuals per age group (40-49, 50-59, 60-64, 65-69, and 70-74 years). This results in a total of 400 participants. A control group of healthy individuals will be recruited from hospital patients undergoing routine screening colonoscopies. Biological and clinical data will be collected at multiple time points throughout the study. Faecal samples will be obtained at baseline, post-treatment, and during the three-year follow-up, accompanied by blood sample collection at each of these time points. Clinical data will include detailed tumour characteristics, such as location, symptoms, and staging, as well as treatment information, including surgery and chemotherapy. Outcomes related to survival and disease progression will also be recorded. Lifestyle and dietary data will be gathered through self-reported questionnaires capturing demographic factors such as age, smoking habits, physical activity, stress levels, and body mass index (BMI). Dietary habits and adherence to the Mediterranean diet will be assessed via telephone interviews. The gut microbiome will be profiled using shotgun metagenomic sequencing, enabling the characterisation of microbial species and functional pathways. This analysis will identify potential correlations between microbiome composition and clinical outcomes, including therapeutic responses and survival rates. For statistical testing, qualitative variables will be analysed using Chi-square or Fisher's exact tests, while quantitative variables will be assessed using Student's t-test or ANOVA. If the normality assumption is not met, Mann-Whitney or Kruskal-Wallis tests will be used. All statistical analyses will be two-sided, with a significance level set at 5%. Expected Outcomes: The study aims to identify biomarkers that enable early, non-invasive CRC detection. Findings will also provide insights into the interplay between lifestyle, diet, and microbiome changes in CRC progression. These insights could lead to personalised preventive strategies and improved therapeutic outcomes.