Colorectal Cancer Incidence and Mortality by Age Group, Colon Location, and Histology in Canada.

INTRODUCTION:Colorectal cancer (CRC) incidence is increasing among younger individuals in many countries. We examined CRC incidence and mortality by age group, site, and histology in Canada. METHODS:Data from the Canadian Cancer Registry and the Canadian Vital Statistics Death Database were used to determine CRC incidence from 1992 to 2019 and mortality from 1974 to 2022. We calculated incidence by age group, site, and histology and mortality by age group and site. Annual percent change was calculated using Joinpoint Regression. Age-period-cohort models with splines were run to indicate influence on CRC incidence. RESULTS:CRC incidence was stable for individuals 20-29 years, increased for those 30-49, remained stable for 50-54, and decreased for 55 years and older. Proximal, distal, and rectal cancer incidence was stable or increased for individuals less than 55 and decreased for those over 55. Adenocarcinoma CRCs increased for those less than 55. Mucinous and signet ring cell CRCs decreased or remained stable for all ages. Neuroendocrine CRCs increased for most ages. Age, cohort, and period effects are evident. CRC mortality stopped decreasing in the late 1990s for individuals 20-49 but decreased for those over 50. Proximal and distal CRC mortality decreased for all ages. Rectal cancer mortality increased. DISCUSSION:CRC incidence and mortality in Canada vary by age, site, and histology. In addition to a reduction in the screening start age, CRC screening programs must focus on individuals 50-54 years of age because they have not experienced a decrease in CRC incidence.