Signet ring cell type and other histologic types: Differing clinical course and prognosis in T1 gastric cancer

Background. The behavior of early stage signet ring cell carcinoma (SRC) is controversial. The purpose of this study was to clarify the behavior of early gastric SRC. Methods. We retrospectively analyzed data from 2,085 patients who had undergone curative gastrectomy for early gastric cancer between 1989 and zoo: Clinicopathologic outcomes and prognoses were evaluated, and we investigated whether these variables were correlated with histopathologic type. Results. Patients with early gastric SRC were younger and had a greater proportion of females than other histologic types. Lymph node metastasis was the only independent prognostic factor for both mucosal and submucosal forms of SRC. Mucosal SRC had a similar rate of lymph node metastasis to poorly differentiated (PD) tubular adenocarcinoma (TUB), and a higher rate than well-differentiated (WD) or moderately differentiated (MD)-TUB. However, its submucosal form had a similar rate of lymph node metastasis to WD-TUB, and a lower rate than MD- or PD-TUB. There was no difference in tumor recurrence or disease-related death according to histopathologic type or depth of invasion. Conclusion. In mucosal gastric cancer, SRC has an unfavorable risk factor of lymph node metastasis than that of others and should not be considered for endoscopic resection. In submucosal gastric cancer, SRC is a more favorable risk factor of lymph node metastasis than that of other histologic types.