Clinicopathologic characteristics of mucinous gastric adenocarcinoma

There has been considerable controversy over the prognosis of mucinous gastric adenocarcinoma (MGC). In this study we analyzed the clinicopathologic differences between MGC and non-mucinous gastric carcinoma (NMGC). In addition, the relationship between mucin content and other clinicopathologic variables, including prognosis in MGC, was also investigated. We reviewed 2118 patients with pathologically-confirmed gastric cancer who underwent gastrectomy at the Department of Surgery, Yonsei University College of Medicine, during the period between Jan. 1987 and Dec. 1993. Among them, 130 patients had gastric carcinoma with extracellular mucin (MGC) and 1988 patients had gastric carcinoma without extracellular mucin (NMGC). We placed the MGC patients into two groups according to mucin content: mucin content involving over 50% of the tumor (dominant type, n = 94) and mucin content involving less than 50% of the tumor area (partial type, n = 36). The results were as follows: MGC was more common in males than NMGC. The size of the tumor in MGC (mean 5.3 cm) was larger than that of NMGC (mean 4.4 cm). The patients with MGC had a higher incidence of Borrmann type IV (MGC: 16.1%, NMGC: 9.9%), more frequent serosal invasion (MGC: 75.4%, NMGC: 48.6%), lymph-node metastasis (MGC: 75.4%, NMGC: 50.7%), and peritoneal metastasis (MGC: 10.0%, NMGC: 3.5%) than patients with NMGC. The patients with MGC were more advanced in stage at the time of diagnosis and had a worse overall 10-year survival rate (44.9%) than patients with NMGC (54.7%). However, the 10-year survival rate according to the stage of MGC was similar to that of NMGC. There were no significant differences between the mucin content and other pathologic variables, including prognosis, i.e. similar biologic behavior between dominant type MGC and partial type MGC. In conclusion, we suggest that MGC was more frequently diagnosed in advanced stage than NMGC with a poorer prognosis and that it is reasonable to consider the carcinoma with mucin content involving more than 30% of the tumor area as MGC.