Is Colonoscopy Alone Adequate for Surveillance in Stage I Colorectal Cancer?

Purpose: While colonoscopy is the standard surveillance tool for stage I colorectal cancer according to NCCN guidelines, its effectiveness in detecting recurrence is debated. This study evaluates recurrence risk factors and patterns in stage I colorectal cancer to inform comprehensive surveillance strategies.

Materials and methods: A retrospective analysis of 2,248 stage I colorectal cancer patients who underwent radical surgery at Samsung Medical Center (2007-2018) was conducted. Exclusions were based on familial history, prior recurrences, preoperative treatments, and inadequate data. Surveillance included colonoscopy, laboratory tests, and CT scans.

Results: Stage I colorectal cancer patients showed favorable 5-year disease-free survival (98.3% colon, 94.6% rectal). Among a total of 1,467 colon cancer patients, 26 (1.76%) experienced recurrence. Of the 781 rectal cancer patients, 47 (6.02%) experienced recurrence. Elevated preoperative CEA levels and perineural invasion were significant recurrence risk factors in colon cancer, while tumor budding was significant in rectal cancer. Distant metastasis was the main recurrence pattern in colon cancer (92.3%), while rectal cancer showed predominantly local recurrence (50%). Colonoscopy alone detected recurrences in a small fraction of cases (3.7% in colon cancer and 14.9% in rectal cancer).

Conclusion: Although recurrence in stage I colorectal cancer is rare, relying solely on colonoscopy for surveillance may miss distant metastases or locoregional recurrence outside the colorectum. For high-risk patients, we recommend considering regular CT scans alongside colonoscopy. This targeted approach may enable earlier recurrence detection and improve outcomes in this subset while avoiding unnecessary scans for the low-risk majority.