Personalized surveillance in colorectal cancer: Integrating circulating tumor DNA and artificial intelligence into post-treatment follow-up

Table 1 Comparison of international guidelines for colorectal cancer surveillance

Surveillance method	ACPGBI (United Kingdom/Ireland)[17]	NCCN (United States)[18,19]	ESMO (Europe)[20,21]	JSCCR (Japan)[22]	CSCO (China)[23]
Clinical exam & CEA	Every 6 months (for 3 years)	Every 3-6 months (years 1-2), then every 6 months (up to 5 years)	Every 3-6 months (years 1-3), 6-12 months (years 4-5)	Every 3 months (years 1-3), every 6 months (years 4-5)	Stage I: Every 6 months; stage II-III: Every 3 months (years 1-3), then every 6 months (years 4-5)
CT	Every 6 months (minimum two evaluations)	Every 6-12 months (up to 5 years), Stage IV: Every 3-6 months (first 2 years)	Every 6-12 months (years 1-3), annually (years 4-5)	Every 6 months (years 1-3), twice per year stage III, annually stages I-II (years 4-5)	Stage III/IV: Every 6-12 months (years 1-5), ultrasound or CT for lower stages
Colonoscopy	Year 1, then every 5 years	Year 1; if adenoma present annually, if no adenoma, repeat at year 3, then every 5 years	Starting year 1, then every 3-5 years	Colon cancer: Years 1 & 3; Rectal cancer: Years 1, 2 & 3	Year 1, then year 3, afterwards every 5 years
Additional imaging	Not routinely recommended	Not routinely recommended	Not routinely recommended	Not routinely recommended	Liver ultrasound recommended for stage II

ACPGBI: Association of Coloproctology of Great Britain and Ireland; CEA: Carcinoembryonic antigen; CSCO: Chinese Society of Clinical Oncology; CT: Computed tomography; ESMO: European Society for Medical Oncology; JSCCR: Japanese Society for Cancer of the Colon and Rectum; NCCN: National Comprehensive Cancer Network.