Does stool collection method affect outcomes in immunochemical fecal occult blood testing?

Area of Science:

• Gastroenterology
• Oncology
• Diagnostic Medicine

Background:

• Colorectal cancer screening is crucial for early detection and improved patient outcomes.
• Immunochemical fecal occult blood tests (iFOBT) are widely used non-invasive screening tools.
• The method of stool sample collection can potentially influence test performance.

Purpose of the Study:

• To compare the positive predictive value (PPV) of iFOBT for colorectal neoplasms.
• To evaluate iFOBT performance using stool from digital rectal examination (DRE) versus routine screening collection.

Main Methods:

• A cross-sectional study involving 1,688 participants undergoing medical check-ups.
• Participants underwent both iFOBT and colonoscopy.
• iFOBT was performed on stool samples collected via DRE and routine screening methods.

Main Results:

• The positivity rate was significantly higher with DRE (5.4%) compared to routine screening (3.5%).
• The PPV for colorectal neoplasms was significantly higher for routine screening (27.1%) versus DRE (19.8%).
• Specifically, PPV for cancer was 20.3% (routine) vs. 15.4% (DRE), and for adenomatous polyps was 6.8% (routine) vs. 4.4% (DRE).

Conclusions:

• Stool samples collected via routine screening demonstrate a superior positive predictive value for detecting colorectal neoplasms compared to those obtained during digital rectal examination.
• Routine screening collection method is recommended for optimizing iFOBT performance in colorectal cancer screening.