Lymph node metastasis occurs in as many as 16% of patients with submucosal invasive
colorectal carcinoma. We investigated the association between histopathological factors and
lymph node metastases in 322 consecutive patients with submucosal invasive
colorectal carcinoma who had undergone radical
colectomy with
lymph node dissection to detect patients at high risk of
lymph node metastasis without measuring the depth of submucosal invasion.
Lymph node metastasis was found in 46 (14.3%) of 322 patients with submucosal invasive
colorectal carcinoma. Univariate analysis showed that each of the following histopathological factors had a significant influence on
lymph node metastasis: invasion depth, lymphatic invasion, venous invasion,
tumor differentiation, growth pattern of the intramucosal
tumor component, complete disruption of the muscularis mucosa due to
tumor invasion, and
tumor budding at the submucosal invasive front. Multivariate analysis showed that lymphatic invasion (P<0.01),
tumor differentiation (P<0.01), and
tumor budding (P<0.01) were significantly associated with
lymph node metastasis. All 46 cases of
lymph node metastasis showed at least one of the following findings: lymphatic invasion, moderately or poorly differentiated
tumor grade,
tumor budding, or complete disruption of the muscularis mucosa due to
tumor invasion. Patients with submucosal invasive
colorectal carcinoma that show at least one of three factors--lymphatic invasion, moderately or poorly differentiated
tumor grade, or
tumor budding--are at high risk for
lymph node metastasis. All of the patients with
lymph node metastasis, who did not have any of these factors, showed a completely disrupted muscularis mucosa.