Prospective multicenter trial of sentinel node mapping for gastric cancer

Abstract

4518 Background: The sentinel node (SN) concept has revolutionized the approach to the surgical staging of both melanoma and breast cancer, and these techniques can yield patient benefit by avoiding various complications due to unnecessary prophylactic regional lymph node dissection in cases with negative SN for cancer metastasis. Clinical application of SN mapping for early gastric cancer had been controversial for years. However, single institutional results of SN mapping for early gastric cancer are almost acceptable results in terms of detection rate and accuracy to determine lymph node status. We hypothesized that SN mapping plays a key role to obtain individual information and allows modification of the surgical procedure for early gastric cancer. Methods: The Japan Society of Sentinel Node Navigation Surgery (JSNNS) has conducted a prospective multicenter trial of SN mapping by a dual tracer method with radioactive colloid and blue dye. Between September 2004 and March 2008, 433 patients with early gastric cancer were accrued at 12 comprehensive hospitals. Patients were enrolled under JSNNS and each institutional review board-approved protocols. Eligibility criteria were that patients had clinically T1N0M0 or T2N0M0 single tumor with diameter of primary lesion less than 4cm without any previous treatments. Technetium-99m tin colloid and isosulfan blue were utilized as dual tracers for SN mapping. Results: SN mapping has been performed for 397 patients with early gastric cancer. Detection rate of hot and/or blue node using our procedure was 97.5% (387/397). The mean number of sentinel nodes per case was 5.6. Fifty-three of 57 cases with lymph node metastasis showed positive sentinel nodes. The sensitivity to detect metastasis based on SN status was therefore 93% in our experience. Accuracy of metastatic status based on SN was 99% (383/387). In two of the four SN false-negative cases, the tumor involved to pT2, and only one case showed the metastatic lymph node beyond the SN basin. Conclusions: Our results suggest that SN concept for clinically N0 early gastric cancer could be validated, and minimized gastrectomy with individualized selective and modified lymphadenectomy for early gastric cancer with negative SN should become feasible and clinically useful as less invasive surgical procedures. No significant financial relationships to disclose.