Lymph node micrometastases in gastric cancer: final results of the Czech multicentre study

Abstract

Lymphadenectomy is an important part of surgical treatment of gastric cancer. Using immunohistochemistry or RT-PCR, small deposits of tumour cells, called micrometastases (MM) and isolated tumour cells (ITC) are found in some of the lymph nodes, which were found negative after a standard examination in haematoxylin eosin (H-E). The aim of this multicentre study was to assess their clinical and prognostic significance. Multicentre, prospective, nonrandomized clinical trial on-going in four Czech centres. The study enrolled patients after radical resection for gastric cancer. All lymph nodes were examined in standard H-E staining, lymph nodes producing negative results were then processed using detailed immunohistochemistry (IHC) with anti-cellular cytokeratin antibody (AE1/AE3, Immunotech). A total of 93 patients following radical surgery for gastric cancer, across the four participating centres were included in the study between the 1st January 2009 and 31st December 2011. A total of 42 patients (representing 45.2 % of the cohort) underwent a resection, while the remaining 51 had a total gastrectomy (54.8 %). A total of 1,588 lymph nodes were found and examined, with the average number of nodes per patient being 17.1. Metastases by H-E stain were found in 441 nodes (27.8 %). The remaining lymph nodes which showed negative after processing in H-E were then examined with IHC. Nodular MM was found in 43 nodes (2.7 %), then the ITC in 74 nodes (4.7 %). No statistically significant difference was observed when comparing the length of survival among patients with negative node findings (H-E negative, IHC negative) and patients with minimal node affection (H-E negative, IHC positive), p = 0.494. Likewise there was no statistically significant difference within the sub-group of patients with minimal node affection between patients with micrometastases (MM) and patients with isolated tumour cells (ITC), p = 0.925. The results of this study indicate that the presence of nodal MM and ITC in gastric cancer is not linked to the worsening of the prognosis of patients. Financially, technically and the time-consuming method of processing nodes with IHC cannot yet be recommended as part of the routine histological examination.