Sentinel lymph node mapping for gastric cancer using a dual procedure with dye- and gamma probe-guided techniques

Increasing evidence supports the sentinel lymph node (SN) concept for melanoma and breast cancers. SN biopsy may replace routine lymph node dissection in the treatment of these cancers. But there are little data evaluating this concept in patients with gastric cancer. The objective of this study was to test the feasibility of SN mapping in gastric cancers by using the dual-mapping procedure with dye and radioactive colloid.

Thirty-one consecutive patients preoperatively diagnosed as T1-2 and N0 underwent SN biopsy using the dual-mapping procedure. Distributions of SNs identified by the dye-guided technique (blue nodes; BNs) were compared with those identified by the gamma probe guided technique (hot nodes; HNs).

Among the 31 patients, 7 were found to have lymph node metastases. All positive nodes were detected by SN biopsy using the dual method. So, an accuracy rate of 100% was achieved in predicting the status of regional lymph nodes. Both BNs and HNs were identified in 28 of 31 patients (90%), but significant discrepancy of distribution was noted between BNs and HNs. Among the 28 patients with identified BNs, there was one metastasis in a non-BN. So the accuracy rate was 96% for the dye-guided technique. In contrast, among the 28 patients with identified HNs, 2 patients had metastasis in non-HNs, making the accuracy rate 93% for the gamma probe-guided technique.

SN mapping is feasible in gastric cancer, but the dye-guided and gamma probe-guided techniques are complementary. So we recommend the dual-mapping procedure.