The total number of retrieved and analyzed lymph nodes is known to impact on survival of patients with gastric cancer. Multiple factors are responsible for the high variability of total lymph node yields. Among these factors, the use of surgical ex vivo lymphodissection may be significant for optimizing the lymph node count.
This article includes our personal experience regarding ex vivo lymphodissection and a meta-analysis which included all the articles related to this topic. We compared two groups of patients with gastric adenocarcinoma who underwent gastrectomy with at least D2 lymphodissection. In the first group, the lymph node count was performed by the pathologist. As for the second, the surgeon performed an ex vivo lymphodissection of the resected specimens before submitting these to the pathologist for further analysis. For the systematic literature review and the meta-analysis, the PubMed database was thoroughly searched, and in order to assess the inter-study heterogeneity, we used I2 and chi2 tests.
The total lymph node yield proved to be significantly higher in the ex vivo lymphodissection group than in the non-ex vivo lymphodissection group (37.4 versus 23.2, p < 0.001). The meta-analysis confirmed our results: the cumulative mean difference between ex vivo lymphodissection and non-ex vivo lymphodissection group is 11.52 (p < 0.00001); inter-study heterogeneity was statistically significant (I2 > 58%, chi2 = 9.63, df = 4, p = 0.05).
Surgical ex vivo lymphodissection increases the total lymph node yield and may lead not only to a more accurate staging of gastric cancer, but also to an improved clinical outcome.