[Extended gastric surgery: is paraaortic lymph node dissection essential for advanced gastric cancer?].

We retrospectively analyzed the clinicopathological findings and prognosis in patients who underwent paraaortic lymph node (No. 16) dissection. No. 16 metastasis was histologically found in 61 of 640 patients (9.5%). Almost all of the patients had tumors in the upper third of the stomach or the whole stomach. In the patients who had a total of ten or less lymph node metastases after curative resection. No. 16 metastases were found at the site of either the left or right side of the abdominal aorta. Conversely, No. 16 metastases occurred in both left and right sides of the abdominal aorta in patients with 11 or more lymph node metastases in total. The five-year survival rate of patients with histologically proven No. 16 metastasis was 21%. The indication for No. 16 lymphadenectomy should be decided by not only the number of No. 16 lymph node metastases but also by the total number of removed lymph node metastases. When D4 lymph node dissection was compared with D2 lymph node dissection in the patients without No. 16 involvement on histology, the prognosis of the former was superior to the latter in the patients with a tumor in the upper and middle part of the stomach. In order to evaluate the efficacy of prophylactic D4 lymphadenectomy, randomized clinical trial between D4 and D2 should be performed. It is also important that the indication for No. 16 lymph node dissection should be decided on the individual patients according to the objective data based on a retrospective study.