High en bloc resection rate achieved by endoscopic mucosal resection with IT knife for early gastric cancer.

BACKGROUND/AIMS: Circumferential endoscopic mucosal resection (EMR) around lesions performed by an insulation-tipped diathermic knife (IT knife) increases en bloc resection rates, suggesting the possibility of expanding indications for EMR. METHODOLOGY: Clinical outcome of EMR performed by IT knife under general anesthesia was evaluated for 26 patients with 29 early gastric cancer. RESULTS: Successful en bloc resection rates obtained by the IT knife were 100, 87.5, 90.0 and 100% for lesions < or =10 mm in size, 11-20 mm, 21-30 mm, and > or =31 mm, respectively. They were significantly higher with the IT knife than those obtained by the conventional method (IT knife method: 93.1% vs. conventional method: 28.5%, p<0.0001). Two lesions were lateral margin positive, and in three cases invasion of lesions was observed as deep as the submucosa. Distal, total, and proximal gastrectomy with D2 lymphadenectomy, respectively, was provided in 3 cases; however, no lymph node involvement was found in any of the resected specimens. Bleeding and perforation were observed in 3 cases, respectively, however, no additional surgical treatment was required for these patients. CONCLUSIONS: EMR by means of the IT knife under general anesthesia can be performed safely and adequately. It is a useful treatment modality for early gastric cancer.

Detection of sentinel lymph nodes in gastric cancers based on immunohistochemical analysis of micrometastases.

BACKGROUND AND OBJECTIVES: The sentinel lymph node (SN) theory has the potential to change the trend of surgery for gastric cancer that is based on wide resection of the stomach with dissection of regional lymph nodes. However, feasibility tests of SN mapping procedures in gastric cancers with analysis of micrometastasis are rare. This study aimed to estimate the clinical usefulness of SN mapping using a dual procedure with dye- and gamma probe-guided techniques for gastric cancers, based on immunohistochemical staining (IHC) analysis. METHODS: SN mapping procedures were performed on 41 patients with T1-T2 gastric cancer, and gastrectomy with D2 lymphadenectomy followed. All SNs and non-SNs obtained from the patients were tested by IHC analysis using anti-cytokeratin antibodies. RESULTS: Using the dual mapping procedure, SNs were detected in all patients (100%). SN was positive in all patients with lymph node metastasis except in one with non-solid type poorly differentiated adenocarcinoma with marked lymphatic permeation, thus achieving an accuracy rate of 98%. CONCLUSIONS: The method was accurate in predicting nodal status and could be an indicator for less invasive treatment in patients with gastric cancer.

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

BACKGROUND: 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. STUDY DESIGN: 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). RESULTS: 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. CONCLUSIONS: 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.