Twenty-three cases of early carcinoma of the rectum, especially the lower rectum were clinicopathologically studied and the policy of the treatment was discussed.
Of all carcinomas of the rectum operated on, early carcinomas of the rectum represented 9.5%, of which 63.5% were early carcinoma of the lower rectum. As to the macroscopic and histological classification of the tumor, IIa (flat-elevated) type and IIa+IIc (flat-elevated with depression) type were frequently seen, and well differentiated adenocarcinoma occupied the majority of the cases (82.9%). Neither “m” cases in which cancer cells were limited within mucosal layer nor “sm” cases in which cancer cells were spreading into submucosal layer had lymph node metastasis. None of 12 “m” cases had venous invasion (v) and lymphatic vessel invasion (ly). In contrast, among 11 “sm” cases, three (27.3%) had ly invasion, four (36.4%) had v invasion, and the level of sm invasion of these cases were all deeper than sm1c.
Early carcinoma of the lower rectum should be undertake polypectomy or local excision and the specimen should be examined histologically in detal. In case of “sm” carcinoma, level of sm-invasion seemed to be one of factors to determine indication for further radical operations.