Preoperative evaluation of early colorectal cancer using an ultrasound mini probe.

Background/aims: We investigated whether endoscopic ultrasonography (EUS) can assess the depth of invasion of early colorectal cancer exhibiting the V pit pattern on magnifying endoscopy with submucosal invasion of 1,000 μm or deeper.

Methodology: Among 38 colorectal tumors exhibiting the V pit pattern on magnifying endoscopy, the findings on EUS with a mini-probe (15 MHz) were compared with histopathological findings. The diagnostic accuracy, sensitivity and specificity of EUS were examined separately in tumors exhibiting the Vi or V5 pit pattern.

Results: Diagnostic accuracy of EUS for cancers exhibiting the Vi pit pattern on magnifying endoscopy with submucosal invasion of 1,000 μm or deeper was 9/15 (60%). Sensitivity was 90%, specificity 14.3%, positive predictive value 31.7% and negative predictive value 76.3%. Diagnostic accuracy of EUS for cancers exhibiting the VN pit pattern on magnify-ing endoscopy with submucosal invasion of 1,000 μm or deeper was 13/18 (72%). The sensitivity and specificity of EUS were 100% and 37.5%, respectively.

Conclusions: EUS tended to diagnose the invasion depth of cancer with submucosal invasion exhibiting the V pit pattern as deeper than it actually was. EUS accurately diagnosed early colorectal cancer with shallow invasion exhibiting the VN pit pattern and surgery was avoided.