Biological characteristics of esophageal squamous cell carcinoma associated with contiguous intraepithelial carcinoma

To evaluate the biological significance of esophageal squamous cell carcinoma that is associated with contiguous intraepithelial carcinoma, we analyzed 95 patients with operated esophageal carcinoma. Of these 95 patients, eight had in situ carcinoma. Among 87 cases in which the tumo had invaded more deeply than the lamina propria, there were 42 cases (48.3%) of contiguous intraepithelial carcinoma associated with the main tumor. The biological characteristics (proliferative activity of cells, as revealed by immunostaining with the Ki-67 monoclonal antibody) of 45 tumors without contiguous intraepithelial carcinoma (group A) were compared with those of 42 tumors with contiguous intraepithelial carcinoma (group B). The more advanced was the main lesion, the lower was the incidence of contiguous intraepithelial carcinoma. The mean Ki-67 score of the main tumors in group A was 51.6% and that of the main tumors in group B was 45.9%. The mean Ki-67 score of the main tumors in group B was very similar to that of the contiguous intraepithelial carcinomas that were associated with the main tumors (44.4%, P = 0.682). Furthermore, the mean Ki-67 score of contiguous intraepithelial carcinomas associated with main tumors was very similar to that of carcinomas in situ (41.2%, P = 0.529). From our results, it is suggested that tumors with high proliferative activity may be assumed to grow rapidly and, as a result, the region of intraepithelial carcinoma may develop into an invasive tumor. By contrast, tumors with low proliferative activity may grow slowly and, in such cases, the carcinoma may remain in the epithelium around the invasive tumor.