Variable interpretation of polyp size by using open forceps by experienced colonoscopists

Area of Science:

• Gastroenterology
• Medical Imaging
• Clinical Trials

Background:

• Endoscopic measurement of colorectal polyps using open forceps is a standard clinical trial practice.
• This method is known to be susceptible to various sources of error, potentially impacting trial accuracy.

Purpose of the Study:

• To evaluate the error rates in determining colorectal polyp size using open forceps.
• Specifically, to assess accuracy at the measurement stage after forceps alignment.

Main Methods:

• Prospective study involving 49 gastroenterologists.
• Participants received training on polyp photographs and then measured test polyps.
• Measurements were analyzed for accuracy within defined margins (25% and 50%).

Main Results:

• Only 37% of polyp size measurements were exact to the millimeter.
• A significant portion of measurements were off by more than 50% (34% larger, 29% smaller).
• However, 47 out of 49 participants measured polyps within a 50% error margin, and 21 were within 25%.

Conclusions:

• Polyp size determination using open forceps is inherently error-prone during the measurement phase.
• A 50% margin of error is suggested for size determination in clinical trials to mitigate these inaccuracies.
• Further research is needed to explore other potential error sources in this measurement technique.