Prognostic value of the number of metastatic lymph nodes in gastric cancer with radical surgery.

To evaluate the effectiveness of extended lymph node dissection in gastric cancer, the relationship between the number of lymph nodes with metastasis and the long-term outcome was studied retrospectively in 761 patients who underwent curative resection with extensive lymph node dissection. The cumulative 5-year survival rate was 85.8% in patients without lymph node metastasis, 60.2% in those with 1-4 lymph nodes, 35.6% with 5-10 nodes, and 12.3% with 11 or more nodes involved. Concerning N2 or N3 patients in whom metastatic lymph nodes would have remained without extensive dissection, the 5-year survival rate was 70.5% in those with 1-4 lymph nodes involved and 44.0% with 5 or more lymph nodes involved when no serosal invasion was observed. It was 38.5% with 1-4 lymph nodes and 5% with 5 or more lymph nodes involved when serosal invasion was observed. These results suggest that extensive lymph node dissection is effective in gastric cancer patients without serosal invasion and, when only a few lymph nodes are involved, also in those with serosal invasion. However, it is not considered to be effective in patients with serosal invasion and metastasis to many lymph nodes. Combination therapies are thought to be required in such patients.