Extracapsular Extension of Pelvic Lymph Node Metastasis is an Independent Prognostic Factor in Bladder Cancer: A Systematic Review and Meta-analysis

Purpose: We aimed to elucidate the relation between extracapsular extension (ECE) and clinical outcomes in node-positive patients following radical cystectomy for bladder cancer. Methods: Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, we searched PubMed, SCOPUS, Web of Science, and Cochrane Library databases from their respective dates of inception until September 2014. Results: Ten articles that met the eligibility criteria included 43–748 subjects per study, with the total number of patients being 1,893. The frequency of ECE ranged from 36.6 to 58.1 %. The pooled hazard ratio (HR) was statistically significant for recurrence-free survival (RFS) [pooled HR 1.56; 95 % confidence interval (CI) 1.13–2.14] and cancer-specific survival (CSS) (pooled HR 1.60; 95 % CI 1.29–1.99) but not overall survival (OS) (pooled HR 1.47; 95 % CI 0.71–3.05). Heterogeneity in RFS (I² 84 %, p < 0.00001) and OS (I² 80 %, p = 0.03) was statistically significant. According to subgroup analysis with meta-regression analyses, “region” (pheterogeneity < 0.0001) and “analysis results” (pheterogeneity < 0.0001) were the sources of heterogeneity. Sensitivity analysis showed that omission of any study did not lead to a significant difference. No statistical evidence of publication bias regarding RFS or CSS was revealed among the studies using Begg’s and Egger’s tests. Conclusions: This meta-analysis shows that ECE is an efficient prognostic factor for node-positive bladder cancer. However, large prospective studies are needed to confirm the clinical utility of ECE as an independent prognostic factor before these results can be applied clinically.