ABSTRACT
BACKGROUND/AIMS: It has been reported that lymph node (LN) metastasis occurs in approximately 10 percent of patients with submucosally invasive colorectal carcinoma. The present study was performed to determine the clinical significance of absolute and relative depth of submucosal invasion and to find the associated pathological risk factors of LN metastasis in submucosally invasive colorectal carcinoma. METHODS: From June, 1989 to May, 1999, 2,580 patients were pathologically confirmed as having colorectal carcinoma. Of these patients, a total of 61 subjects with submucosally invasive carcinoma could be reviewed pathologically and were included in this retrospective analysis. The relative depth of submucosal invasion was evaluated by Kudo (sm1, 2, 3) and modified Haggitt (L1, 2, 3) classifications, and the absolute depth was measured. RESULTS: The absolute depth of submucosal invasion was significantly correlated with the relative depth evaluated by both Kudo and modified Haggitt classifications (p<0.01). Of 51 patients in whom the status of LN metastasis could be evaluated, six (11.8%) showed LN metastasis. Among the patients with LN metastasis, there was no one with sm1 or L1 in the relative depth and 500 micrometer or less in the absolute depth. The risk of LN metastasis was related to the gross type, and lymphatic or vessel invasion (p<0.05). CONCLUSIONS: The risk factors for LN metastasis in submucosally invasive colorectal carcinoma were the gross type and lymphatic or vessel invasion. The results also suggest that the absolute depth of submucosal invasion might be a useful parameter to select the patients for the endoscopic treatment.