Detailed incidence and mortality trends of early-onset colorectal cancer in Canada.

Abstract

e15539 Background: There has been a consistent increase in the incidence of early-onset colorectal cancer (eoCRC), under the age of 50, in Canada since the late 1990s. Questions remain surrounding how these trends vary by topography, histology, and stage, and related trends with CRC-specific mortality. Methods: CRC incidence data were obtained from the Canadian Cancer Registry and CRC-specific mortality data from the Canadian Vital Statistics – Death Database for the years 2000 to 2017. Age-specific average annual percent changes (AAPC) in the incidence (by topography and histology) and mortality rates of CRC were estimated using the National Cancer Institute’s Joinpoint Regression Program. To determine age-specific differences (5-year age groups) in CRC diagnosis at late stage (III and IV) for years 2011 to 2017 combined, a logistic regression model adjusting for sex with the 50-54 age group as the referent was conducted. Results: AAPCs and 95% confidence intervals in the rates of incidence (topography and histology) and mortality of eoCRC from 2000 to 2017 in Canada are presented in Table. Different trends in topography were observed across sexes with the largest increases in the distal colon (splenic flexure, descending, and sigmoid) and rectum among males and rectum only among females. Significant increases were observed for non-mucinous adenocarcinomas, while significant decreases were observed for mucinous adenocarcinomas among the 40-49 age group. Compared to the 50-54 age group, only the 45-49 group had a significantly higher odds of developing late-stage colon cancer, while men and adults 25-49 had a higher odds of developing late stage rectal cancer. Despite increases in the incidence of eoCRC there has only been a significant increase in mortality for men aged 20-39. Trends in mortality vary by site, with significant decreases observed for colon cancer-specific mortality among the 40-49 age group and increases in rectal cancer-specific mortality for adults aged 20-49. Conclusions: These results indicate that the largest increases in incidence and mortality for eoCRC have occurred in the rectum and trends have varied by sex. Further research on the etiology and treatment outcomes of eoCRC patients are warranted for this patient population.[Table: see text]