Distribution of the deepest penetrating point of minute submucosal gastric cancer.

BACKGROUND Accurate assessment of depth of invasion is critical in decision-making for additional surgery after endoscopic resection of early gastric cancer (EGC). Although this depth of invasion is determined at the deepest point of submucosal invasion (DPSI), there is no literature describing the distribution of deepest invasion point. OBJECTIVE To describe the location of the DPSI, and to determine whether it is possible to predict this point by clinicopathological features before treatment. METHODS One hundred and ninety-five lesions of EGC with minute submucosal invasion, which had been resected en bloc between 1991 and 2003, were reviewed. For each lesion, we recorded the location of the DPSI as being in one of three areas demarcated by three concentric equal distance rings. We also examined the correlation between the location of the deepest penetration and the clinicopathological characteristics. RESULTS The DPSI was located most often (53%) in the central, less often (31%) in the middle and least often (16%) in the outermost area. There was no significant correlation between the distribution of the deepest point and any clinicopathological features. CONCLUSIONS The DPSI was not always in the central area, and it was impossible to predict its location by clinicopathological features alone. To obtain an accurate measure of depth of tumor invasion, we must histologically assess the entire lesion by thin sections.