Sentinel lymph node biopsy with 99mTC tin-colloid in patients with gastric carcinoma.

Background/aims: The sentinel lymph node (SLN) is defined as the first draining node from the primary lesion. The objective of this study was to determine the feasibility of SLN biopsy in patients with gastric cancer for assessment of lymph node status.

Methodology: From November 2001 through to July 2002, SLN biopsy was performed in twenty-two consecutive patients whose preoperative imaging studies showed T2 or T1 and no lymph node metastasis. Three hours prior to each operation, 99mTc tin-colloid (2.0ml, 1.0mCi) was injected into the submucosa of gastric tumor via endoscope. After SLN biopsy had been performed using gamma probe (NEO2000 Gamma Detection System, Neoprobe CO, 1999, USA), all the patients underwent radical gastrectomy. The SLN was cut and immediately manipulated for frozen section, and processed to make paraffin block for H&E and immunohistochemistry (IHC) staining.

Results: On average, 1.8 (range 1-5) SLNs were identified per patient. The location of all SLNs was in the perigastric area. No skip metastases were found. SLNs were identified in 20 of the 22 patients (success rate, 90.9%). The sensitivity of the SLN status in the diagnosis of the lymph node status was 82.2% (5/6) and the specificity was 100.0% (14/14). The diagnostic accuracy according to SLN status was 95.0% (19 of 20).

Conclusions: SLN biopsy using radioisotope in patients with gastric cancer was a technically feasible procedure and a minimally invasive approach in the assessment of the nodal status in each patient.