Incidence of age migration of colorectal cancer in younger population: Retrospective single centred-population based cohort study

Background: The positive correlation between the incidence of colorectal cancer and age is well known. However, current data demonstrates that there is noticeable age migration in the incidence of colorectal cancer towards young adults highlighting that this disease should no longer be considered to solely affect the elderly. The aim of the study is to analyse the changes in the trend for the age at which colorectal cancer presents, to identify if there is an appreciable age migration towards a younger population. Methods: This is a retrospective observational cohort study on a single-centred population. Data was obtained from The Luton and Dunstable University Hospital Colorectal Cancer Database. It was analysed from three separate decades from the years 1999, 2009, 2019 and 2020. All patients newly diagnosed with colorectal cancer in these time periods were included in this study. Gender, anatomical site, and the stage migration was also analysed. Results: A total of 598 patients were diagnosed with colorectal cancer in the specified time periods. The overall age-specific incidence rates had risen throughout the three decades. Notably the incidence rate had doubled between 1999 and 2009. In the younger adult population of <40 years, the incidence rate had risen seven-fold across three decades with a disproportionate increase among females compared to males. Stage migration is also analysed over the three decades with no evident difference in anatomical position of the tumour. Conclusion: There has been an upwards trend in the incidence of colorectal cancer among the younger population. This will have implications for investigation and screening in the future