Gastric cancer histology: Clinicopathologic characteristics and prognostic value

Background and Objectives: Gastric cancer can be divided into two major histologic categories, that is, differentiated and undifferentiated types. In the present study, we sought to clarify the prognoses and clinicopathologic characteristics of signet ring cell carcinoma and mucinous carcinoma, both of which are mucin-producing tumors of the undifferentiated type. Methods: We retrospectively reviewed medical records of 2,275 patients who underwent gastric resection. Cases were divided into four histologic groups: differentiated carcinoma (well differentiated and moderately differentiated, WMD), poorly differentiated (PD), signet ring cell carcinoma (SRC), and mucinous carcinoma (MC). Results: The overall cumulative 5-year survival rates for patients were 67% for WMD, 54% for PD, 65% for SRC, and 48% for MC. The outcome of SRC was similar to that of WMD, whereas that of MC was similar to that of PD. Stage-stratified analysis revealed that histologic type was not statistically related to survival in patients with stage I, II, or III. On the other hand, histologic type in patients with stage IV disease was found to be significantly associated with survival. Conclusions: Histologic classifications of mucin-producing gastric cancers should separately be considered from other histologic types.