The pathway to diagnosis of early-onset colorectal cancer: exploring diagnostic intervals and their effect on outcomes

Early-onset colorectal cancer, diagnosed before 50 years (EOCRC), is rising. Previous studies suggest younger patients experience longer diagnostic intervals potentially contributing to poorer outcomes. A prospective cohort study comparing EOCRC patients in Canterbury, Aotearoa New Zealand, with a control group of late-onset patients (65+ years, LOCRC). Pathways to diagnosis and diagnostic intervals were compared. Sixty-three consecutive EOCRC patients were compared 64 LOCRC patients. The younger cohort was more likely to have advanced disease (stage four in 32% v 17%). Pathways to diagnosis were comparable between the groups (p > 0.05). EOCRC patients, however, visited their GP more frequently before diagnosis (p = 0.04), and 40% had an appraisal interval (time from symptoms to seeking medical advice) exceeding 3 months compared to 26% of LOCRC patients, though this was not significant (p = 0.146). Stage four EOCRCs were less likely to have appraisal intervals >3 months (OR 0.28, p = 0.046). Pathways to diagnosis were similar between EOCRC and LOCRC patients. Shorter diagnostic intervals were associated with advanced disease, indicating that shortening diagnostic intervals alone may not improve outcomes. Diagnosing CRC prior to symptoms develop (screening) is likely the best way to improve outcomes.