Benign regional lymph nodes in gastric cancer on multidetector row CT.

BACKGROUND: Benign regional lymph nodes (LNs) are sometimes enlarged in gastric cancer patients due to reactive or inflammatory changes. Frequently these enlarged LNs can mimic LN metastasis and lead to overstaging.
PURPOSE: To assess frequency of benign regional LNs in gastric cancer patients compared with that in a healthy population and to assess the frequency of benign regional LNs in gastric cancer according to T-staging.
MATERIAL AND METHODS: Between August 2005 and June 2009, 177 patients with surgically proven gastric cancer without LN metastasis (TanyN0M0) who had previously undergone preoperative multidetector row CT (MDCT) and 168 healthy patients who visited the healthcare center and underwent an abdominal MDCT were included in this retrospective study. An abdominal radiologist evaluated the distribution of regional LNs and measured the short diameter of LNs ≥6 mm, ≥8 mm, and ≥10 mm. The number of enlarged benign LNs was compared between the two groups, and the distribution of LN with regard to T-stage of gastric cancer was also evaluated.
RESULTS: At least one LN ≥6 mm, ≥8 mm, and ≥10 mm was detected in 64.4% (114/177), 22.0% (39/177), and 4.0% (7/177) of patients in the gastric cancer group, respectively, compared to 29.8% (50/168), 4.2% (7/168), and 0% of patients in the healthy group, respectively. The difference between the two groups was statistically significant (P <0.0001). The LN ≥8 mm was found in 14.9% (20/134) in early gastric cancer (T1), and 44.2% (19/43) in advanced cancer (T2 or higher); the difference was statistically significant (P = 0.0002). However, the frequency of LN ≥6 mm in mucosal cancer (T1a) and submucosal cancer (T2b) was not significantly different, regardless of its size.
CONCLUSION: Benign regional LNs ≥6 mm are more frequently detected in gastric cancer patients than in a healthy population and in advanced gastric cancer than in early cancer.