Ten patients with primary gastric non-Hodgkin's lymphoma (NHL) were pr
eoperatively assessed by endoscopic ultrasonography (EUS). Tumor infil
tration depth and lymph node involvement were assessed using the TNM c
lassification system. EUS was 80 % accurate in determining the T(L) st
age and 90 % in detecting lymph node metastases (N(L) stage). Based on
the longitudinal tumor extent (antrum to fundus), as assessed by preo
perative (n = 10) and additionally, intraoperative EUS (n = 3), partia
l gastric resection was performed in nine patients and total gastrecto
my in one. All resection specimens had tumor-free resection margins (R
O resection rate 100 %). These results were compared to those in 23 pa
tients with gastric NHL operated on prior to the introduction of EUS i
n the hospital who were comparable with respect to tumor location and
extent. In comparison with the ten cases where treatment was guided by
EUS, the rate of total gastrectomy was higher (65 % versus 10 %) and
the R0 resection rate lower (72 % versus 100 %) in this group of 23 pa
tients. These results show that EUS may play a crucial role in the pre
-surgical staging of gastric NHL.