Sentinel lymph node mapping and biopsy using radioactive tracer in gastric cancer

Background Lymph node metastasis is one of the most important prognostic factors in gastric cancer survival. Sentinel lymph node (SLN) mapping and biopsy may reduce the extension of lymph node dissection by determination of lymph node involvement. The current study prospectively evaluates the feasibility and reliability of SLN biopsy in gastric cancer. Methods A total of 30 patients with gastric cancer with a preoperative imaging stage of T1-T2 or T3, N0 and M0 were enrolled in the study. Furthermore, 2-16h prior to each operation, 99mTc-sulphur colloid solution (0.5mL, 2mCi/mL) was endoscopically injected into the submucosal layer around the primary lesion. Lymph nodes were examined using a hand-held gamma probe. Subsequently, a total or subtotal gastrectomy and D2 lymphadenectomy was performed in each patient. Results The success rate of SLN biopsy was 100%. Sensitivity, specificity, positive predictive value and negative predictive value were 91.7%, 100%, 100% and 75%, respectively. Both of the two false-negative cases were in the T3 group. In cases of T2 tumours, the sensitivity was 100%. Discussion SLN biopsy using a gamma probe in early stage gastric cancer seems to be a safe, feasible and accurate procedure with high sensitivity in predicting regional lymph node involvement.