The incidence of early-onset colorectal cancer (eoCRC) has been increasing in North America. Debate remains as to whether the trends by topography, histology, stage, or mortality in this population are amenable to intervention from screening.
CRC incidence (2000–2017) and mortality (2000–2018) data were obtained from the Canadian Cancer Registry and Vital Statistics. Annual percentage changes (APC) in the incidence (topography and histology) and mortality of eoCRC were estimated using joinpoint regression. Incidence of late-stage CRC (III or IV) versus early-stage CRC (I or II) was compared between the eoCRC (age 20–49 years) and eligible screening (age 50–74 years) groups with Poisson regression.
Among women aged 20–49 years, the incidence of CRC significantly increased from 2000 to 2017 in both the distal colon (APC = 1.40) and rectum (APC = 3.00), whereas for men aged 20–49 years, the CRC incidence increased in the proximal colon (APC = 1.10), distal colon (APC = 3.00), and rectum (APC = 3.70). Among both men and women aged 20–49 years, the incidence of nonmucinous adenocarcinomas significantly increased (APC: 1.90 and 2.30, respectively), whereas mucinous adenocarcinomas decreased for women (APC = −1.60) and remained stable for men. Adults aged 30 to 49 years, when diagnosed with CRC, had a significantly higher risk of being diagnosed with a late-stage CRC compared with those in the age group of 50–74 years. Rectal cancer mortality increased from 2000 to 2018 in the eoCRC group (APC for women and men 3.80 and 3.40, respectively).
Emerging data support future modifications to guidelines on screening for eoCRC in Canada. Further research is required on the effect, cost-effectiveness, and risk prediction for targeted screening within this group.