Optimal Surveillance Strategy After Positive FIT and Negative Colonoscopy

In colorectal cancer screening programs based on fecal immunochemical testing (FIT), a subgroup of individuals presents with strongly positive FIT results but negative findings on subsequent high-quality colonoscopy. Despite the absence of detected adenomas or cancer, these individuals may remain at increased risk of colorectal cancer.

Currently, there is no consensus guideline regarding the optimal follow-up strategy for this population. Some clinicians recommend repeat colonoscopy, while others prefer non-invasive monitoring using FIT.

This pragmatic randomized controlled trial will compare two surveillance strategies:

Repeat FIT testing two years after enrollment

Direct colonoscopy two years after enrollment

The primary objective is to compare the detection rate of advanced colorectal neoplasia (ACN) between the two strategies. The results of this study may help establish evidence-based surveillance guidelines for this high-risk population.

Inclusion criteria

• Age 45-74 years
• Quantitative FIT result with fecal hemoglobin ≥100 µg/g within the past two years
• Negative high-quality colonoscopy following the positive FIT result
• Ability to provide written informed consent

Exclusion criteria

• History of colorectal cancer
• Inflammatory bowel disease
• Known hereditary colorectal cancer syndrome
• Life expectancy less than five years
• Inability or unwillingness to undergo colonoscopy