Prognostic significance of signet ring cell carcinoma of the stomach.

A retrospective analysis of 3,702 gastric cancer patients operated on between 1981 and 1991 was carried out to compare the clinicopathological features of signet ring cell (SRC) gastric cancer with other cell types. Four hundred and fifty patients (12.2%) had signet ring cell gastric carcinoma. There was a tendency for patients with the signet ring cell gastric cancer to be younger and female, and of the middle-third part of stomach to be involved. The proportion of early gastric cancers in signet ring cell gastric cancers was 43%, which was significantly higher than in the other histological types [33% in well differentiated (WD) type, 23% in moderately differentiated (MD) type, and 13% in poorly differentiated (PD) type]. Early stage signet ring cell gastric carcinomas were less invasive in depth and had less lymph node metastasis. However, signet ring cell gastric cancers in advanced stage were more invasive and had more lymph node metastasis than other cell types. There was no significant difference in five year survival rates (5YSR) among patients with different histological cell types in early stage gastric cancers. But, in advanced gastric cancers, the prognosis for patients with the signet ring cell type was significantly worse than for the other types (SRC, 31.9% 5YSR; WD, 45.1% 5YSR; MD, 38.4% 5YSR; PD, 34.5% 5YSR) (P < 0.05), which can be explained by the finding that advanced gastric cancers with signet ring cell type have a larger tumour size, more lymph node metastasis, a deeper invasive depth and more Borrmann type 4 lesions than other histological types. This study suggests that signet ring cell gastric cancer may have a different biological behaviour.