Interrater Agreement of Height Assessment by Rigid Proctoscopy/Rectoscopy for Rectal Carcinoma

Area of Science:

• Colorectal Surgery
• Oncology
• Diagnostic Imaging

Background:

• Current guidelines use a 12cm cutoff for neoadjuvant chemoradiation in rectal carcinoma, measured by rigid endoscopy.
• Rigid endoscopy is operator-dependent, potentially impacting treatment decisions based on minor measurement differences.

Purpose of the Study:

• To evaluate the agreement of rigid rectoscopic tumor height measurements among experienced examiners.
• To assess tumor palpability and anal verge to anocutaneous line distance.
• To determine if patient positioning (lithotomy vs. left lateral) affects measurements.

Main Methods:

• Prospective observational study at an academic teaching hospital.
• 50 rectal carcinoma patients (70% male, median age 72.5 years) were included.
• Four experienced examiners performed tumor height measurements, with interrater agreement analyzed.

Main Results:

• Excellent interrater reliability (ICC=0.947) was found for tumor height assessment.
• Despite high reliability, 26% of patients showed disagreement on the <12cm or >12cm height limit.
• Significant disagreement was also noted for tumor palpability and anal verge distance.

Conclusions:

• Rigid rectal endoscopy measurements alone are insufficient for determining neoadjuvant therapy eligibility.
• Universal height limits ignore biological variability; consider patient frame, gender, and pelvic descent.
• Standardized MRI/CT protocols incorporating pelvic anatomy are recommended for improved decision-making.