Metachronous Advanced Neoplasia in Early Onset Colorectal Cancer

BACKGROUND: The risk of post-operative metachronous advanced colorectal neoplasia (MAN) among patients with sporadic average-onset colorectal cancer (AOCRC: ≥50 years) is well studied, whereas comparative risk in early-onset colorectal cancer (EOCRC: <50 years) remains unclear. Post-operative CRC surveillance guidelines are primarily based on studies in AOCRC cohorts and may not represent optimal post-operative surveillance intervals in EOCRC. AIMS: To compare the incidence of MAN between patients with sporadic AOCRC and EOCRC and to identify clinical risk factors associated with MAN. METHODS: In this retrospective cohort study, patients with EOCRC and AOCRC who underwent ≥1 postoperative surveillance lower endoscopies between 2011-2021 were included. Patients with inflammatory bowel disease, total proctocolectomy, and hereditary CRC syndromes were excluded. The most advanced metachronous lesion detected during postoperative surveillance was categorized as normal, nonadvanced neoplasia (NAN), or MAN. RESULTS: 230 EOCRC patients and 504 AOCRC patients (median age 44 and 66, respectively) were included. Overall rates of MAN were similar between EOCRC and AOCRC groups (13% vs. 16.1%, p = 0.342), however, AOCRC patients had a significantly lower MAN-free survival than EOCRC patients. In EOCRC patients, metachronous NAN, as the most advanced lesion detected during follow-up, was less frequent (17% vs. 26%, p = 0.009), the interval between CRC surgery and first surveillance endoscopy was shorter, and the follow up time was longer than in AOCRC patients. Older age, smoking exposure, and a distally located (descending and/or sigmoid colon) index cancer were independently associated with the development of MAN. CONCLUSION: Our study did not identify a sufficiently increased burden of MAN in EOCRC to support an age-specific surveillance strategy. Smoking is associated with MAN and should be avoided in CRC patients.