Estimating the size of colorectal polyps endoscopically: random guess or systematic error?

Area of Science:

• Gastroenterology
• Endoscopic Imaging
• Oncology

Background:

• Colorectal polyp size is crucial for assessing malignancy risk and defining advanced lesions.
• Significant variations exist in endoscopists' ability to accurately estimate polyp size.
• Accurate polyp size estimation is vital for appropriate patient management and treatment decisions.

Purpose of the Study:

• To investigate the linear relationship between endoscopically estimated polyp size and actual pathologic size.
• To quantify the accuracy of endoscopic polyp size estimation.
• To identify potential systematic errors in endoscopic polyp size assessment.

Main Methods:

• Retrieved data from a prospectively recorded polyp database for completely removed, single-piece adenomas.
• Compared endoscopic estimates of maximum polyp diameter with pathology report measurements.
• Utilized linear regression analysis to determine the relationship between endoscopic and pathologic sizes.

Main Results:

• Analyzed 126 polyps from 126 patients (85 male, 41 female; mean age 63.2 years).
• Mean endoscopic polyp size was 12.2 mm (±9.3 mm) versus mean pathology size of 9.3 mm (±6.9 mm).
• Linear regression revealed a significant relationship (r²=0.761), with a formula to adjust endoscopic estimates: endoscopic size = 0.7 + 1.175 × pathology size.

Conclusions:

• A linear relationship exists between endoscopic and pathologic colorectal polyp sizes across all diameters.
• The findings suggest a systematic error in endoscopic polyp size estimation.
• Accurate endoscopic assessment requires calibration against pathologic measurements for reliable clinical decision-making.