Endoscopic Ultrasound Sonography Including High-Frequency Ultrasound Probes
With the widespread availability of endoscopic mucosal resection (EMR) or endoscopic submucosal dissection (ESD), it is important to differentiate Tis and T1a cancers (T1 cancer with <1000 μm submucosal invasion depth) from T1b cancers (T1 cancer with ≥1000 μm submucosal invasion depth). Endoscopic ultrasonography (EUS), including high-frequency ultrasound probes (HFUPs), is a unique diagnostic modality obtaining sectional images similar to histopathological findings. Under the best scanning conditions by EUS (with HFUPs), the normal colonic wall is visualized as a nine-layered structure, and the muscularis mucosa and intermuscularis propria layers can be visualized. A total of 274 cases were subjected to EUS, and the overall accuracy rate was 77.3% (211/274) for the choice of therapy. The accuracy rate was significantly higher in T1b carcinomas (87.3%) than in Tis-T1a carcinomas (69.2%) (p < 0.001; chi-square test) and significantly higher in F&D-type carcinomas (82.8%) than in polypoid-type carcinomas (69.9%) (p < 0.001). In Japan’s rapidly aging society, the combination of EUS and EMR/ESD is expected to become popular and accepted as a standardized treatment for achieving a radical cure of T1 carcinomas with a subsequent reduction in the number of unnecessary additional surgeries.
KeywordsEndoscopic ultrasound sonography (EUS) High-frequency ultrasound probes (HFUPs) Colorectal T1 (SM) carcinoma Endoscopic resection Endoscopic submucosal dissection (ESD) Endoscopic total excision for T1b carcinomas
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