早期大腸癌の深達度診断におけるEUSと拡大内視鏡の位置づけ―EUSを重要視する立場から

Efficacy of High-Frequency Ultrasound Probes for Invasion-Depth Diagnosis of Colorectal Cancers

要旨　1997年4月から2000年9月までの期間に経験した大腸癌94例96病変を対象として，内視鏡通常観察単独での深達度診断能と超音波細径プローブ所見を加味した診断能を比較検討した．内視鏡通常観察単独，細径プローブ単独での深達度正診率はそれぞれ81％，77％（描出困難例を除くと94％）であったが，内視鏡通常観察に細径プローブ所見を加味することで正診率は92％へと上昇した．表面型と隆起型に分けて検討したところ，表面型では内視鏡通常観察に細径プローブ所見を加味した正診率は100％であった．一方，隆起型では内視鏡通常観察に細径プローブ所見を加味した正診率は78％であり，隆起型に対する正診率向上が今後の課題と考えられた．

　To evaluate the usefulness of high-frequency ultrasound probes (HFUP) for invasion-depth diagnosis of colorectal cancers, we retrospectively compared the diagnostic accuracy of colonoscopy, HFUP, and the combination of these two methods. Between April 1997 and September 2000, 94 patients (96 lesions) with colorectal cancers were examined by colonoscopy and HFUP. The diagnostic accuracy of colonoscopy and HFUP were respectively 81% and 77% (94%, excluding the cases where adequate quality of images for evaluation was not available). The diagnostic accuracy was improved to 92% by combining the two. We also compared the diagnostic accuracy for superficial type cancers and protruded type cancers. The diagnostic accuracy of the combination of colonoscopy and HFUP was 100% in the former and 78% in the latter. These results indicate that HFUP is useful for invasion-depth diagnosis of superficial type cancers, but is not particularly valuable for the diagnosis of protruded type cancers.