Risk of lymph node metastasis and prognostic outcome in early gastric cancer patients with mixed histologic type.

Background: Whether early gastric cancer with mixed histologic type should be considered for endoscopic submucosal dissection (ESD) remains controversial. The objective of this study was to evaluate the risk of lymph node metastasis (LNM) and prognostic significance for early gastric cancer with mixed histologic type. Methods: We retrospectively reviewed clinicopathologic and survival data of 302 patients who underwent surgical resection for early gastric cancer. Based on the histologic components, all patients were classified as pure differentiated type, pure undifferentiated type and mixed histologic type. The prognostic differences between different types were compared and predictive factors for LNM were evaluated. Results: Histopathologically, the proportion of mixed histologic type was 12.3% in early gastric cancer. In terms of LNM, mixed histologic type had a more frequent incidence than pure differentiated type (32.4% vs 11.1%, P < 0.01). However, there was no significant difference between mixed type and pure undifferentiated type for LNM (32.4% vs 21.1%, P = 0.139). Multivariate analysis revealed that tumor size >2 cm (odds ratio [OR]: 2.153, 95% confidence interval [CI]: 1.113-4.164, P < 0.05), submucosal invasion (OR: 3.881, 95%CI: 1.832-8.222, P < 0.001), lymphovascular invasion (OR: 8.797, 95% CI: 2.643-29.277, P < 0.001), undifferentiated type (OR: 3.146, 95% CI: 1.352-7.320, P < 0.01), and mixed histologic type (OR: 3.635, 95% CI: 1.272-10.390, P < 0.05) were independent risk factors for LNM in early gastric cancer patients. However, mixed histologic type did not affect the survival outcome of these patients (hazard ratio: 0.629, 95% CI: 0.074-5.311, P > 0.05). Conclusion: Mixed histologic type was an independent risk factor for lymph node metastasis in early gastric cancer patients. The decisions regarding endoscopic submucosal dissection for mixed histologic type should be carefully considered. (c) 2020 Elsevier Inc. All rights reserved.