Is age just a number? Causal modeling of recurrence risk in rectal cancer

Background: Evidence is emerging that the incidence of colorectal cancer is increasing in young adults, but the descriptive epidemiology required to better understand these trends is currently lacking.Methods: A population-based cohort study was carried out including all adults aged 20-49 years diagnosed with colorectal cancer in England between 1974 and 2015.Data were extracted from the National Cancer Registration and Analysis Service database using ICD-9/10 codes for colorectal cancer.Temporal trends in age-specific incidence rates according to sex, anatomical subsite, index of multiple deprivation quintile and geographical region were analysed using Joinpoint regression.Results: A total of 56 134 new diagnoses of colorectal cancer were analysed.The most sustained increase in incidence rate was in the group aged 20-29 years, which was mainly driven by a rise in distal tumours.The magnitude of incident rate increases was similar in both sexes and across Index of Multiple Deprivation quintiles, although the most pronounced increases in incidence occurred in the southern regions of England.Conclusion: Colorectal cancer should no longer be considered a disease of older people.Changes in incidence rates should be used to inform future screening policy, preventative strategies and research agendas, as well as increasing public understanding that younger people need to be aware of the symptoms of colorectal cancer.Presented to a conference of the Association of Coloproctologists of Great Britain and Ireland, Dublin, Ireland,