The risk of lymph node metastasis in mucosal gastric carcinoma: Especially for a mixture of differentiated and undifferentiated adenocarcinoma

Background/Aims: Endoscopic submucosal dissection (ESD) is gaining wider acceptance for the treatment of early gastric carcinoma (EGC) and its indication has been extended to mucosal gastric carcinoma with undifferentiated component in some institutes. Our aims were to confirm the frequency of lymph node metastasis in such cases and clarify the demarcation in indications for ESD. Methodology: We evaluated medical data of 287 patients with mucosal gastric carcinoma who underwent surgical resection between 1996 and 2008. The tumours were histologically classified into purely differentiated (PD), differentiated-predominant mixed (DPM), undifferentiated-predominant mixed (UPM) and purely undifferentiated (PU) types. Results: Lymph node metastasis was identified in seven (2.4%) of the 287 patients and was detected more frequently in UPM (10%, two of 20) and PU (4%, four of 98), compared with PD (none of 148) (p=0.01 and 0.02, respectively). In mixed-type carcinoma, size was a significant risk factor for lymph node metastasis (p=0.04). Conclusions: It might be better to select gastrectomy rather than ESD for the treatment of mucosal gastric carcinoma with an undifferentiated component.