Clinicopathological characteristics and prognosis of signet ring cell carcinoma of the stomach.

Background: Signet ring cell carcinoma (SRC) of the stomach is a histological type based on microscopic characteristics. Although the distinctive clinicopathological features of SRC have been reported, results are inconsistent and survival outcomes are uncertain.

Methods: We retrospectively studied 769 patients with gastric carcinoma who underwent gastrectomy in our institute from 1999 to 2009. Among them, 326 patients (42.4 %) had early gastric cancer (EGC) and 443 patients (57.6 %) had advanced gastric cancer (AGC). Sex, age, tumor location, macroscopic type, tumor size, microscopic invasion, and survival rate were compared between patients with SRC, differentiated-, and undifferentiated-type gastric carcinomas.

Results: Fifty-one patients (15.6 %) had SRC in EGC; there were significant differences in sex, age, location, macroscopic type, and size between SRC and the differentiated histological type. However, there was no difference between SRC and undifferentiated-type gastric carcinoma, except for the macroscopic type. Fifty-seven patients (12.9 %) had SRC in AGC. Sex, age, location, size, macroscopic type, perineural invasion, N stage, and hepatic metastasis were significantly different between SRC and the differentiated histological type. Undifferentiated-type gastric carcinoma differed in sex, macroscopic type, and hepatic metastasis. The overall survival rate differed between SRC and other cell types (P < 0.001). Among all the study patients, age [hazard ratio (HR) 1.013, P = 0.041] and tumor, node, and metastasis (TNM) stage (HR 2.350, P < 0.001) were important factors for predicting survival. Omitting patients with palliative resection or metastases, TNM stage was still an important factor for survival (HR 2.077, P < 0.001).

Conclusions: Patients with SRC showed similar clinicopathological features with undifferentiated histology. The survival of patients with SRC reflected a better prognosis in patients with undifferentiated gastric carcinoma. However, when narrowing the patients to those with EGC only, survival in EGC patients exhibited no difference between histological types. Among AGC patients, SRC patients had a worse prognosis than other cell types.