Predictive factors for lymph node metastasis in esophageal squamous cell carcinomas contacting or penetrating the muscularis mucosae: the utility of droplet infiltration

Background Tissue features to predict the presence or absence of lymph node metastasis (pN) in cases of esophageal squamous cell carcinoma found to contact or penetrate the muscularis mucosae (m3) on endoscopic mucosal resection (EMR) have yet to be clarified in detail. This study was conducted to determine the utility of droplet infiltration (DI) as a candidate. Methods In 27 m3 esophageal squamous cell carcinoma cases who underwent esophagectomy, DI parameters (longitudinal diameter, DIs; number of constituent cells, DIn; distance from the primary focus, DId) for droplet infiltration were examined to allow comparison with vessel permeation (VP) as a predictive factor for lymph node metastasis. Results DIs ≤ 20 μm, DIn ≤ 4, and DId ≥ 200 μm all demonstrated relations with pN (P = 0.001, 0.006, and 0.03, respectively). As predictive factors for lymph node metastasis, DIs ≤ 20 μm and DIn ≤ 4 had sensitivity and likelihood ratios (LR) equal to or higher than VP. Conclusions Tissue features of DI (DIs ≤ 20 μm and DIn ≤ 4) can be applied as predictive factors for lymph node metastasis in m3 esophageal cancers after EMR. This is the English version of a research paper reported in Gastroenterol Endosc 2004;46:2086–94.