[Optimal nodal dissection for early gastric cancer]

Extensive lymphadenectomy (D2) in 295 patients with early gastric cancer (EGC) resulted in a significantly lower 10-year recurrence rate than limited lymph node dissection (D1) in 97 patients (2.1% vs. 11.9%, p < 0.005). Among node-positive patients, the recurrence rate following D2 was significantly lower than that after D1 (12.5% vs. 44.4%, p < 0.02). Among node-negative patients, there was no difference in recurrence rate between two groups (0.6% vs 3.3%, p < 0.2). These observations suggest that there are two optimal methods of node dissections in EGC surgery based on nodal status. The sentinel node concept is important to understand nodal status. In 1993, we developed intraoperative endoscopic lymphatic mapping with 2% patent blue to demonstrate the lymphatic basins in EGC. Frozen sections of the blue nodes in 203 patients had a high predictive value for nodal metastasis, with a sensitivity of 89%, specificity of 100%, and accuracy of 98%. Four false-negative cases had clinical metastasis, which was diagnosed at surgery. In 34 of 35 patients, metastatic nodes were located along the lymphatic basins. Among them, 15 patients had metastasis only in the sentinel lymph nodes. Of 5 gastric lymphatic basins, 42% of the patients had involvement of one, 47% 2, and 12% 3. These results show that each EGC has its own lymphatic basins in which metastasis can develop. The more numbers of the sections there are, the higher the likelihood of nodal metastasis. This means that each frozen section slice carries the risk of being false negative. Therefore we should always dissect the lymphatic basins even in cases with no sentinel node metastasis. In addition, patients with sentinel nodes containing metastasis should be treated with the D2 procedure.