Endoscopic follow-up in colorectal cancer: Comparisons and critical issues across different guidelines

Table 1 Comprehensive tests for oncologic follow-up based on National Comprehensive Cancer Network, European Society for Medical Oncology and Italian Association of Medical Oncology guidelines

Exam/assessment	Post-surgical patients (colon/rectum)
Clinical visit + medical history + physical examination	Every 3-6 months for 3 years, then every 6-12 months up to 5 years
Serum CEA	Every 3-6 months for 2 years, then every 6 months up to 5 years (only if candidates for curative surgery)
Colonoscopy	At 1 year after surgery, then at 3 years, then every 5 years (more frequently if advanced polyps or incomplete resections)
Rectoscopy/flexible sigmoidoscopy	In patients with rectal resection, every 6-12 months for 2-3 years
Pelvic MRI	Not routine; reserved for high-risk rectal tumors
Chest-abdomen-pelvis CT scan	Every 6-12 months for 3 years, then annually up to 5 years (for high-risk stage II and stage III)
Emerging biomarkers (ctDNA)	Not routinely recommended; use in clinical trials

CEA: Carcinoembryonic antigen; MRI: Magnetic resonance imaging; CT: Computed tomography; ctDNA: Circulating tumor DNA.