Detection of Micrometastases in the Sentinel Lymph Node from Patients with Early Gastric Cancer

Jung, Myung Sun; Kim, Wook; Kim, Won Woo; Kim, Jeong Soo; Jin, Hyung Min; Park, Cho Hyun; Jeon, Hae Myung; Park, Seung Man; Lim, Keun Woo; Kim, Seung Nam

Abstract

PURPOSE: If the SLN (sentinel lymph node) is an accurate predictor of the lymph node status it should eliminate unnecessary lymph node dissection, resulting in a lower morbidity and mortality in patients with an early gastric cancer. The aim of this study was to investigate the feasibility of SLN biopsy for its location, accuracy and ability to sensitize the tumor cell detection, using reverse transcriptase-polymerase chain reactions (RT-PCR) for the cytokeratin 19 and CD44 variants.
METHODS
SLN biopsies were performed in patients with early gastric cancer (n=33). After a gastrectomy to the apposite site, isosulfan blue dye (0.5-1.0 ml) was injected submucosal medially, laterally, superiorly and inferiorly, adjacent to the tumor site. Lymphatic channels were immediately apparent. Sentinel nodes were separately submitted, and evaluated with RT-PCR, using the cytokeratin 19 and CD44 variants. Following the removal of the sentinel node, the adjacent regional nodes were also removed. Both SLN and non-SLN were examined with H&E stain and RT- PCR.
RESULTS
Sentinel nodes could be identified in 26 of 33 patients (79%). The average number of sentinel nodes detected was 1.4 and were chiefly perigastric nodes. Of these 26 patients, 6 had micrometastasis in their sentinel nodes by RT-PCR detection using the cytokeratin 19 and CD44 variants. The specificity of the SLN status in the diagnosis of the lymph node status was 95% (20/21). One patient (4%) had skip metastasis.
CONCLUSION
A SLN biopsy, using indocyanine green, can be performed with a high success rate. A focused examination of the sentinel nodes detected by indocyanine green with RT-PCR will resolve the underestimation of micrometastasis in regional lymph nodes, and improve the accuracy of the pathological staging. If the sentinel node concept is clinically feasible for early gastric cancer, we would perform not only accurate staging, but also effective surgical treatment, with minimally invasive techniques.