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-2 = 85.1%) and DFS (HR: 1.17, 95%CI: 1.00-1.37, P = 0.040; I-2 = 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-2 = 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-2 = 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-2 = 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.