Clinicopathological Differences between Mucinous Adenocarcinoma and Signet-Ring Cell Carcinoma in the Colorectum

Abstract

Purpose. This study aimed to evaluate the clinicopathological differences between signet-ring cell carcinoma and mucinous adenocarcinoma of the colon and rectum.Methods. We prospectively reviewed the medical records between January 2000 and December 2007, and identified 19 patients with signet-ring cell carcinoma and 192 patients with mucinous adenocarcinoma. We examined the differences in age, tumor location, pathologic stage, pre-operative carcinoembryonic antigen level, microsatellite instability, and 5-year overall survival between each subtype.Results. The patients with signet-ring-cell carcinoma (mean age, 60.4 years) were slightly younger than patients with mucinous adenocarcinoma (mean age, 65.6 years; p=0.001). In addition, the incidence of mucinous adenocarcinoma and signet-ring cell carcinoma was higher in right-sided colon cancer (35.4% and 36.8%) than in other subtypes of colorectal cancer (25%). Further, no significant difference was observed in gender, preoperative carcinoembryonic antigen level, high probability of microsatellite instability, and tumor recurrence rate between the 2 subtypes. Signet-ring cell carcinoma was more likely to present at the later stages (stage III/IV, 100.0%) than mucinous adenocarcinoma (stage III/IV, 64.1%; p＜0.001). The 5-year overall survival rates of patients with signet-ring cell carcinoma were poorer than those of patients with mucinous adenocarcinoma (29.5% vs. 57.8%; p＜0.001). Patients with signet-ring cell carcinoma (17.6%) had significantly poorer cancer-specific survival than those with mucinous adenocarcinoma (51.1%; p＜0.001).Conclusion. Colorectal signet-ring cell carcinoma patients had advanced disease and poorer outcome than mucinous adenocarcinoma patients. No significant difference was observed in microsatellite instability analyses between signet-ring cell carcinoma and mucinous adenocarcinoma.