Different prognostic significance of signet ring cell histology for early and advanced gastric cancer patients: a systematic review and meta-analysis.

Objective: To review relevant studies and perform a meta-analysis to evaluate the prognostic significance of signet ring cell (SRC) histology for gastric cancer (GC) patients.

Methods: Systematic literature search was performed using PubMed and Embase databases. The relevant data were extracted and the association between SRC histology and survival outcome were evaluated using a fixed-effect or random-effect model.

Results: A total of 21 studies were included in this meta-analysis. The prevalence of SRC histology varied from 8.7% to 50%. SRC histology type was associated with poorer OS (HR: 1.12, 95%CI: 1.01-1.23, P = 0.034; I = 85.1%) and DFS (HR: 1.17, 95%CI: 1.00-1.37, P = 0.040; I = 63.6%). The subgroup analysis indicated that SRC type had a better OS than non-SRC type for early GC patients (HR: 0.60, 95%CI: 0.48-0.75, P < 0.001; I = 33.7%). However, it was a poor prognostic factor for advanced GC when excluding stage IV patients (HR: 1.18, 95%CI: 1.07-1.29, P < 0.001; I = 6.5%). SRC type had a higher risk of peritoneal recurrence than non-SRC type (OR: 1.36, 95%CI: 1.06-1.75, P = 0.017; I = 1.3%).

Conclusion: SRC type had a distinctly different prognostic significance for early and advanced GC patients. SRC type was associated with better survival outcomes in early GC patients, but it was a predictive factor for poor survival in advanced GC patients.