Neural Invasion is a Significant Contributor to Peritoneal Recurrence in Signet Ring Cell Gastric Carcinoma.

BACKGROUND: Gastric signet ring cell carcinoma (SRC) has shown a favorable outcome in early stages but has a worse prognosis than non-SRC in advanced stages. However, the cause for this stage-dependent prognostic impact has not been determined. This study aimed to compare clinicopathologic features and recurrence patterns between gastric SRC and non-SRC in a cohort of Eastern patients.

METHODS: This study reviewed the prospectively collected data of 764 patients undergoing curative resection for gastric cancer from 2005 to 2008. The demographics, clinicopathologic characteristics, disease-specific survival (DSS) rate, and recurrence-free survival (RFS) rate of the patients were analyzed.

RESULTS: The SRC patients (n = 176) had a worse prognosis than the non-SRC patients (n = 588), especially in stages T3 and T4. Peritoneal recurrence and the incidence of neural invasion (NI) were significantly increased in the SRC patients, albeit only in stages T3 and T4. In the T3 and T4 patients with NI, peritoneal recurrence occurred more frequently in SRC than in non-SRC (28.7% vs. 13.7%; p = 0.001), but not in the T3 and T4 patients without NI. Only in the patients with NI, SRC led to a significantly shorter DSS (67.6 vs. 90.7 months; p = 0.008) and RFS (67.1 vs. 80.3 months; p = 0.036) than non-SRC.

CONCLUSIONS: This report is the first to present the relationship between NI and peritoneal recurrence as the cause of stage-dependent prognoses for SRC. A better understanding of NI may lend insight into cancer spread and recurrence, especially in gastric SRC.