[Pattern of lymph node metastasis and extent of lymphadenectomy for distal gastric cancer]

To analyze lymph node (LN) metastasis patterns and determine the appropriate extent of LN dissection in distal-third gastric cancer.

Clinical data of 545 patients with distal third gastric cancer undergoing radical operation in the Fujian Provincial Hospital between 2001 and 2010 were analyzed retrospectively. The metastasis rate for each LN station was analyzed stratified by the depth of tumor invasion.

The incidence of LN metastasis in this cohort was 38.2% (208/545). LN metastasis rate in mucosal cancer was 2.0% (2/99) and involved LNs were limited to station 1 LN stations. LN metastasis rate in submucosal cancer was 18.9% (18/95), significantly higher than that in mucosal cancer (P<0.01). The metastasis rates to groups No.7, 8 and 9 in station 2 were 5.3% (5/94), 3.2% (3/94), and 1.1% (1/89) respectively. In addition, 3 cases (3.2%) had metastasis in station 2 outside the range of groups 7, 8 and 9 including groups No.1, 11p and 12. Gastric cancer invading the muscularis propria or deeper layers showed an significant increased rate of metastasis (P<0.01).

D1 dissection seems to be sufficient for mucosal cancer. Standard D2 dissection should be performed for cancers of the muscularis propria or deeper. For submucosal cancer, an extended D1+ dissection is required for complete removal of metastatic nodes.