Predictive factors for lymph node metastasis in signet ring cell gastric cancer and the feasibility of endoscopic submucosal dissection

PURPOSE

Endoscopic submucosal dissection has recently been practiced on a differentiated type of early gastric cancer. However, there is no clear evidence for endoscopic treatments of signet ring cell carcinoma. The aim of this study is to identify the predictive clinicopathological factors for lymph node metastasis in signet ring cell carcinoma for assisting endoscopic submucosal dissection trials.

MATERIALS AND METHODS

A total of 186 patients with early signet ring cell carcinoma who underwent radical curative gastrectomy between January 2001 and September 2009 were enrolled in this study. Retrospective reviews of their medical records are being conducted. Several clinicopathologic factors were being investigated in order to identify predictive factors for lymph nodes metastasis: age, gender, tumor size, type of operation, tumor location, gross type, ulceration, Lauren's classification, depth of invasion, and lymphatic invasion.

RESULTS

The lymph node metastasis rate for signet ring cell carcinoma was 4.3% (n=8). Of the 186 lesions with early signet ring cell carcinoma, 91 (48.9%) tumors were larger than 15 mm in size and 40 (21.5%) showed submucosal invasions in the resection specimens. In multivariate analysis, only the lymphatic invasion (P<0.0001) showed an association with lymph node metastasis. To evaluate cutoff values for tumor sizes in the presence of lymph node metastasis, early signet ring cell carcinomas with lymphatic invasions were excluded. In the absence of lymphatic invasion, mucosal cancer with tumor sizes <15 mm had no lymph node metastasis.

CONCLUSIONS

Endoscopic submucosal dissection can be performed on patients with early signet ring cell carcinoma limited to the mucosa and less than 15 mm.

Clinical outcomes of endoscopic submucosal dissection for undifferentiated or submucosal invasive early gastric cancer

Background/Aims

Early gastric cancer (EGC) that is undifferentiated or shows submucosal invasion has not been generally accepted as an indication for endoscopic treatment. But recently, experiences with endoscopic submucosal dissection (ESD) for undifferentiated EGC or submucosal invasive (SM) EGC have increased. The aim of this study was to evaluate clinical outcomes of ESD for EGC with undifferentiation or submucosal invasion.

Methods

Between August 2005 and August 2009, among 210 EGCs treated using ESD at our hospital, 18 lesions were diagnosed as undifferentiated gastric cancer and 41 as SM gastric cancer. A retrospective analysis was done on the medical records of these patients.

Results

Mean follow-up periods were 19.39±11.2 months. During the follow-up period, local recurrence was noted in 4 lesions. Local recurrence rates of the EGC groups (group 1, mucosal cancer with undifferentiation; group 2, SM cancer with differentiation; group 3, SM cancer with undifferentiation) were 10%, 4.5%, and 50%, respectively. Groups 1 and 2 were not significantly different in local recurrence rates compared to the mucosal cancer with differentiation group (p=0.061, p=0.125, respectively). The undifferentiated EGC group was significantly lower in curability using ESD than the differentiated EGC group (55.6% vs. 89.6%, p=0.000). The curability of the SM EGC group was lower than the mucosal EGC group (36.6% vs. 98.9%).

Conclusions

Complete resection using ESD is difficult in undifferentiated and SM gastric cancers. SM cancer with undifferentiation should be treated immediately by salvage operation. For mucosal cancer with undifferentiation or SM cancer with differentiation, one should consider careful short-term follow-up.