Preliminary Study for Sentinel Lymph Node Biopsy with 99MTc Tin-Colloid in Patients with Gastric Cancer

ABSTRACT

PURPOSE: The sentinel lymph node (SLN) is defined as the first draining node from the primary lesion and it would be the first site of metastasis. The objective of this study was to determine the feasibility of an SLN biopsy in patients with gastric cancer for the assessment of the lymph node status. METHODS: From November 2001 through to March 2002, SLN biopsies were performed in fourteen consecutive patients whose preoperative imaging studies showed T2 or T1 and no lymph node metastases. Three hours prior to each operation, a 99mTc tin-colloid (2.0 ml, 1.0 mCi) was injected via endoscopy into the patient's gastric submucosa. Subsequently a lymphoscintigraphy was performed serially using a dual head gamma camera. After a SLN biopsy had been performed using the gamma probe (NEO2000TM Gamma Detection System, Neoprobe CO, 1999, USA), all the patients underwent a radical gastrectomy (D2+alpha). The SLN was cut into three pieces for a frozen sample, H&E and immunohistochemistry (IHC) staining. RESULTS: The location of all the SLNs was in the perigastric area. No skip metastases were found. SLNs were identified in 12 of the 14 patients (success rate, 85.7%). Of these 12 patients, 6 had lymph node metastases in SLNs or Non-SLNs, or both; 3 in both SLNs and non-SLNs; 2 in SLNs alone; and 1 in non-SLNs alone. The sensitivity of the SLN status in the diagnoses of the lymph node status of the patient was 82.2% (5/6) and the specificity was 100.0% (6/6). The diagnostic accuracy according to SLN status was 91.7% (11 of 12). CONCLUSION: SLN biopsies using a radioisotope in patients with gastric cancer are a technically feasible and accurate technique; they are a minimally invasive approach in the assessment of the node status of patients with gastric cancer.