Intramucosal gastric cancer: the rate of lymph node metastasis in signet ring cell carcinoma is as low as that in well-differentiated adenocarcinoma.

Objective: Endoscopic resection (ER) plays a major role in the management of early gastric cancer. Less lymph node metastasis (LNM) and better survival rates were reported in early gastric signet ring cell carcinoma (SRC) than adenocarcinoma. We investigated and compared the clinicopathologic characteristics of endoscopic and surgical features in early gastric SRC and adenocarcinoma in accordance with histologic differentiation to examine the feasibility of ER in early gastric SRC.

Methods: From January 2003 to September 2011, patients diagnosed with early gastric cancer among patients who had undergone a curative gastrectomy with lymph node dissection were enrolled. Patients' age, sex, tumor size, location, macroscopic type, depth of invasion, lymphovascular invasion (LVI), and LNM were determined.

Results: A total of 696 patients were enrolled. SRC was more frequent in women and more common at the mid-body than differentiated adenocarcinoma. SRC was more common in patients younger than 50 years of age (P < 0.001) and the elevated type was less common in SRC than other adenocarcinomas (P < 0.001). The incidence of submucosal invasion, LVI, and LNM in SRC were similar to well-differentiated adenocarcinoma. Moderately and poorly differentiated group, tumor size greater than 20 mm, submucosal invasion, and LVI were independent risk factors predicting LNM. Intramucosal SRC less than 20 mm had no LNM.

Conclusions: Rate of LNM and submucosal invasion in early SRC was as low as those in early well-differentiated adenocarcinoma. ER for early gastric SRC may be an alternative to surgical gastrectomy under certain conditions.