Height of Rectal Cancer: A Comparison between Rectoscopic and Different MRI Measurements

Area of Science:

• Oncology
• Radiology
• Medical Imaging

Background:

• Accurate rectal cancer height determination is crucial for treatment planning and prognosis.
• Rigid rectoscopy is the current gold standard for measuring tumor height from the anal verge.
• Non-invasive imaging techniques are being explored as alternatives to rigid rectoscopy.

Purpose of the Study:

• To compare rigid rectoscopy with three MRI measurement techniques for rectal cancer height.
• To evaluate MRI measurements from the anal verge as a potential alternative to rigid rectoscopy.
• To determine optimal MRI cut-off values for categorizing rectal tumor height.

Main Methods:

• Retrospective study of 106 rectal cancer patients.
• Comparison of rigid rectoscopy (gold standard) with three MRI measurement techniques (MRI1-3) on T2w sagittal scans.
• Analysis of agreement between MRI measurements and rigid rectoscopy using UICC classification and ROC analysis.

Main Results:

• Fair correlation was observed between rectoscopy and all three MRI techniques.
• Substantial agreement was found for MRI1 (r=0.66) and MRI3 (r=0.67) compared to rigid rectoscopy.
• New proposed MRI cut-off values for tumor height categorization were established for each technique.

Conclusions:

• MRI measurements using MRI1 and MRI3 techniques are interchangeable and valid alternatives to rigid rectoscopy.
• These MRI methods offer a reliable non-invasive approach for determining rectal cancer height.
• Further validation of these MRI techniques can improve treatment planning for rectal cancer.