| Theme |
Prevalence of the IIc type colorectal neoplasm |
| Title |
Incidence of and clinicopathological characteristics of depressed type lesions: baseline findings of multicentre retrospective cohort study |
| Author |
Tatsuya Okuno |
Division of Gastrointestinal Oncology and Endoscopy, National Cancer Center Hospital East |
| Author |
Yasushi Sano |
Division of Gastrointestinal Oncology and Endoscopy, National Cancer Center Hospital East |
| Author |
Yasuo Ohkura |
Depertment of Surgical and Molecular Pathology, Dokkyo University School of Medicine |
| Author |
Shin-ei Kudo |
Digestive Disease Center, Showa University Northern Yokohama Hospital |
| [ Summary ] |
The concept and diagnosis of flat and depressed type lesions, as precursor lesions related to the so-called de novo route in colorectal cancer development, has been widely accepted especially in Japan. However, the incidence and clinicopathological characteristics of these tumors are both obscure. The aim of this multicenter retrospective cohort study is to determine the incidence and clinicopathological characteristics of flat and depressed colorectal lesions in Japan. The cases were patients who were refered for total colonoscopy at nine institutes in Japan up to July 2002, not having a familial or personal history of polyposis, HNPCC, or inflammatory bowel disease. Clinicopathological analysis was verified for these lesions having submucosal invasion at each institutes, to investigate the incidence and clinicopathological characteristics of flat and depressed colorectal lesions. Patients enrolled in this study, at nine institutes had 66,670 lesions which were treated with surgical or endoscopic resection and displayed submucosal invasion. The incidence of lesions histological characteristics of depressed lesions was 1.89% (95% CI: 1.78-2.0%). The difference in frequency of intramucosal high grade dysplasia between these institutes was not significant [51.2% (95% CI: 49.1-54.3%)]. Small discrepancies were seen in the histological diagnosis and incidence of flat and depressed lesions these nine institutes. Flat and depressed lesions are regarded as rare types of tumors, however, they belong to a distinct subset which demonstrates greater biological aggressiveness in the prevalence of the intramucosal high grade dysplasia. Accordingly, we should not overlook these lesions and further studies are needed to formulate a standard terminology concerning flat and depressed lesions in other countries. |