Esophagus/Stomach/Small IntestineCould the immune response in the sentinel lymph nodes of gastric cancer patients be the key to tailored surgery?

BackgroundPrecise detection of downstream, nonsentinel lymph node metastases is the key to implementation of the sentinel lymph node concept in gastric cancer. To overcome the problem of complex lymphatic drainage, micrometastases, and skip metastases, we investigated the feasibility of tumor cell detection in sentinel lymph nodes, using flow cytometry as well as studied immune suppression in the sentinel lymph node as a potential marker of downstream lymph node metastases.MethodsIn 21 patients with gastric cancer, the sentinel lymph nodes extracted during operation subjected to frozen sections and flow cytometry. The tumor cells were defined with the cell surface markers CEACAM and EpCAM. Simultaneously, the cell densities of different subsets of T cells were determined.ResultsThe sensitivity and specificity of the determination of nodal status with flow cytometry for tumor cell detection was 100% and 63%, respectively, as seen in frozen sections. Correlations with nonsentinel lymph node metastases were seen for CD127lowCD25high and CD45negCD127lowCD25high cell densities, relative proportion of CD45RAnegCD127lowCD25high cells, frozen sections results, lymphangial invasion, and tumor size (P ≤ .043 each). Multivariate analysis identified the relative proportions of CD45RAnegCD127lowCD25high cells as the only significant predictor for downstream nonsentinel lymph node metastases (P = .028; 95% confidence interval, 1.107-5.780). The predictive value of combined detection of flow cytometry tumor cells and the relative proportion of CD45RAnegCD127lowCD25high cells for nodal stage determination was 91%.ConclusionCombined detection of tumor cells and CD45RAnegCD127lowCD25high cells in sentinel lymph nodes with flow cytometry predicts accurately nonsentinel lymph node metastases.