Evaluation of the Indication for Endoscopic Mucosal Resection in the Lesions of Submucosal Invading Colorectal Cancer. Sigmoid Colon Is Also the Risk Factor of Lymph Node Metastasis

Abstract

Aim: Colorectal submucosal invading cancer (sm cancer) is a boundary lesion between endoscopic mucosal resection (EMR) and conventional surgery with regional lymph-node (LN) resection. Because the frequency of LN metastasis is about 10% in the lesion of sm cancer, a large number of cases with this lesion can be cured by EMR. In the present study, we assess the correlation between LN metastasis and parameters, and extract significant factors by multivariate statistical analysis from these parameters and clarify the indication of EMR. Patients and Methods: During the period from July 1985 to April 2005, a total of 426 lesions of sm cancers were detected. We treated 266 carcinomas endoscopically and 160 carcinomas surgically. 123 sm cancers, which were resected endoscopically as the initial treatment, were followed by surgical colectomy because of the possibility of LN metastasis. 283 sm cancers were finally selected for this study. The depth of vertical invasion in the submucosal layer was measured from muscularis mucosae to the deepest cancer gland in micrometer. The patterns of infiltrating growth into the submucosal layer were further divided into two groups: expanding growth with a distinct border, and infiltrating growth with an indistinct border. Result: 1. As for patterns of invasion, the frequencies of LN metastasis in the groups of expanding growth and infiltrating growth were 0.8% (1/119) and 11.6% (19/164), respectively (p = 0.0011). 2. The frequencies of LN metastasis in the lesions of lymphatic permeation positive and venous invasion positive were 14/84 (1.73%, p = 0.0002) and 6/68 (8.8%, p = 0.5912) respectively. 3. As for the location of cancer, LN metastasis is statistically significant high rate in the sigmoid colon (Odds ratio: 3.178, 95% CI: 1.226-8.237). 4.There was no significant relationship between depth of vertical invasion and LN metastasis (P = 0.3432). 5. The results of multivariate statistical analysis from these significant parameters were as follows: infiltrating growth pattern (Odds ratio:14.113, 95% CI:1.73-115.149, p = 0.013); lymphatic permeation positive (Odds ratio:6.319, 95%CI: 2.083-19.169, p = 0.001); sigmoid colon (Odds ratio:4.901, 95% CI:1.664-14.435, p = 0.004). Conclusion: The significant factors which extracted by multivariate statistical analysis were infiltrating growth pattern, lymphatic permeation positive and tumor location of sigmoid colon. The frequencies of LN metastasis were 8/24 (33.3%) in the cancers with all these three factors on the one hand and 0/62(0%) in the cancers with none of these three factors on the other hand (p = 0.0001).