| [ Summary ] |
The aim of this retrospective study was to evaluate the usefulness of magnifying colonoscopy (CF200Z, Olympus) in the assessment of the depth of invasion in colorectal cancer. A total of 4,563 specimens, resected at our center between July 1992 and January 1998, were studied retrospectively. There were 3,954 adenomas or intramucosal cancers and 609 carcinomas with submucosal or deeper invasion. The lesions were classified into two groups based on their appearance at endoscopy ; (1) Non-depressed types (574 lesions appearing polypoid or flat) and (2) Depressed types (26 lesions). The incidence of sm or deeper invasion of the non-depressed type was 86% in lesions larger than 31mm in diameter, and 94% in the depressed type lesions larger than 11mm in diameter. Therefore, the usefulness of magnifying endoscopy should be evaluated, for the lesions of non-depressed type less than 30mm in diameter and of depressed type less than 10mm in diameter. Accuracy rates for depth of invasion were 90% (516/574) in non-depressed type, and 96% (25/26) in depresssed type. Magnifying endoscopy is anticipated to be useful for diagnosing the depth of invasion in colorectal cancer. |