Development of Type Is Carcinomas in Colorectal Submucosal Invasive Cancer, from a Radiologic Viewpoint Hiroyuki Kobayashi 1 , Tadahiko Fuchigami 1 1Institute of Gastroenterology, Matsuyama Red Cross Hospital Keyword: 大腸sm癌 , X線扁平率 , 無茎性早期大腸癌 , Is型定義 pp.1437-1450
Published Date 1997/10/25
DOI https://doi.org/10.11477/mf.1403105220
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 We classified 231 sessile elevated lesions of early colorectal cancers, including elevated lesions with central depression, into two types of Is and Ⅱa according to our criteria and compared clinicopathological differences between the two types. Initially, from the results of primary analysis of 68 operated cases, we defined Is and Ⅱa type carcinomas by considering their types of origin in intramucosal cancers as follows; Lesions of which the pathological flat rate (height/size of the lesion in resected specimen×100%: PFR) was over 20% were Is type, and the others were Ⅱa type. Then, according to this definition, we determined the type of cancers which were to be treated endoscopically from the radiologic flat rate (height of lateral view/size of enface view of the lesion by barium enema×100% RFR) instead of PFR, because RFR was almost identical with PFR in the primary analysis. Of 231 lesions, Is were 183 (m: 104, sm: 79) and Ⅱa were 48 (m: 21, sm: 27). Size of Ⅱa, according to the degree of invasion, was smaller than that of Is. However, the frequency of sm2 and sm3 invasive cancers in Ⅱa was higher than that of Is. Ⅱa cancers with depression were regarded to develop from intramucosal cancers to sm3 invasive cancers. However, Is cancers with depression were recognized to be sm2, and sm3 invasive cancers.

 From the comparison of adenomatous components in cancers according to the degree of invasion, it was speculated that Is grew mainly through the root of the adenoma-carcinoma sequence, and that Ⅱa grew mainly through the root of the de novo cancer. Thus, it is considered that our classification of Is and Ⅱa is significant in respect to the development of sessiled elevated lesions of early colorectal cancers from the clinicopathological difference between the two types.

Copyright © 1997, Igaku-Shoin Ltd. All rights reserved.


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