Prognostic significance of neuroendocrine differentiation in breast carcinoma: a meta analysis

Neuroendocrine differentiation (NED) has been observed in breast carcinoma (BC). Several studies have explored the prognostic significance of NED in patients with BC but yielded controversial results. In order to comprehensively appraise the prognostic significance of NED in BC, we carried out the present meta-analysis with the risk ratios (RRs) of 5-year and 10-year survival rates and hazard ratios (HRs) of overall survival (OS) and disease-free survival (DFS) as outcomes of interest. Multiple databases including PubMed, FreQuest and Web of science were searched for literature retrieval. The pooled RRs and HRs with corresponding 95% confidence intervals (CIs) were computed to estimate the prognostic significance of NED in BC patients. All the incorporated studies were high quality based on our quality assessment. The pooled RRs suggested that BC patients with NED had a significantly higher risk of death within 5 years and 10 years than those without NED (5-year survival rate: RR=2.338, 95% CI: 1.2694.309, P=0.006; 10-year survival rate: RR=1.227, 95% CI: 1.010-1.490, P=0.039); the pooled HRs indicated that BC patients with NED had significantly worse OS and DFS than those without NED (OS: HR=1.826, 95% CI: 1.1972.786, P=0.005; DFS: HR=2.539, 95% CI: 1.915-3.367, P<0.001). No significant publication bias was observed among these analyses. In conclusion, our meta-analysis demonstrates that the NED is significantly associated with unfavorable prognosis, and BC patients with NED are more likely to have poor prognosis.