Multiple rounds of one sample versus two sample faecal immunochemical test-based colorectal cancer screening: a...

Area of Science:

• Gastroenterology
• Oncology
• Public Health

Background:

• Colorectal cancer (CRC) screening using fecal immunochemical tests (FIT) requires multiple rounds for maximum effectiveness.
• Intermittent bleeding from advanced neoplasia can lead to missed diagnoses with single-sample FIT.
• Limited research exists on multi-round screening using two-sample FIT (2-FIT).

Purpose of the Study:

• To compare the effectiveness of multiple rounds of one-sample FIT (1-FIT) versus 2-FIT screening.
• To evaluate differences in participation rates, positive predictive value (PPV), diagnostic yield, and interval CRC detection.
• To determine the optimal FIT strategy for population-based CRC screening.

Main Methods:

• A population-based study invited asymptomatic individuals aged 50-74 for four rounds of 1-FIT or 2-FIT screening every two years.
• Participants received one or two FIT kits per round, with a fecal hemoglobin cutoff of 10 μg/g for colonoscopy referral.
• Data on participation, positivity rates, PPV for advanced neoplasia, diagnostic yield, and interval CRC were collected and analyzed.

Main Results:

• Participation rates were slightly higher for 1-FIT (74.7%) compared to 2-FIT (72.5%).
• Cumulative positivity rates were significantly higher for 2-FIT (28.5%) versus 1-FIT (19.2%).
• Despite higher positivity, 2-FIT showed a lower cumulative PPV for advanced neoplasia (24.2% vs. 33.0%) and no significant difference in diagnostic yield (4.7% vs. 4.4%) or interval CRC detection (0.1% vs. 0.1%) compared to 1-FIT.

Conclusions:

• Four rounds of 2-FIT screening did not significantly improve diagnostic yield or reduce interval CRC compared to 1-FIT.
• 2-FIT screening resulted in higher colonoscopy demand without proportional benefits in advanced neoplasia detection.
• 1-FIT colorectal cancer screening programs are recommended over 2-FIT programs based on these findings.