Abstract
Endoscopic ultrasonography was performed in 56 patients with colorectal cancer to evaluate the invasion and lymph node metastasis. The instruments employed were echo-colonoscopes, XCF-UM1 and XCF-UM2 (Olympus). A scope could be inserted into the site of lesion in all cases. Ultrasonographic visualization of the lesion was, however, possible in 40 cases (71.4%). Visualization was possible in all cases of rectal cancer ; the rate of visualization tended to be lower when the lesion was located in other sites. The proportion of the lesion to the total circumference and the degree of narrowing tended to inversely correlate with the rate of visualization. The rate was higher in cases with early cancer compared to those with advanced disease ; in the latter patients, the rate tended to be higher when the lesion was protruded. The extent of invasion was correctly evaluated in 36 (90%) out of 40 cases in which visualization was possible. When ultrasonographic visualization was possible, the rate of correct diagnosis of invasion was unrelated to the site of lesion, the proportion of the lesion to the total circumference, the degree of narrowing, or the extent of invasion. Metastasis to the lymph nodes beneath the wall could be detected in 7 (41.2%) out of 17 cases in which lymph node metastasis was proved. Reactive lymph node swelling was observed in 2 cases ; ultrasonographic differentiation was impossible between metastatic and reactively swollen lymph nodes. Endoscopic ultrasonography can yield important information for the recognition of cancer extention. The usefuleness of the examination is, however, limited when the narrowing in remarkable. The development of echocolonoscope with smaller caliber is desired.
