Survival prognosis and clinicopathological features of the lymph nodes along the left gastric artery in gastric cancer: implications for D2 lymphadenectomy.

The Japanese Gastric Cancer Treatment Guidelines (third edition) have assigned No. 7 station left gastric artery lymph nodes (LNs) to the D1 range of lymphatic dissection. We investigated the clinicopathological characteristics, survival impact, and appropriateness of ascribing No. 7 station LNs to D1 lymphadenectomy in gastric cancer. Patients (n=608) undergoing radical resection with No. 7 station LN dissection were recruited between January 1997 and June 2008. They were subdivided into four groups: N0, no LN metastasis; D1, LN without No. 7 station LN metastasis in the D1 lymphadenectomy region; No. 7, No. 7 station LN without LN metastasis in the D2 lymphadenectomy region; and D2, LN without No. 7 station LN metastasis in the D2 lymphadenectomy region. Of these, 17.2% (n=105) were positive for No. 7 LN metastasis, an important, independent prognostic factor associated with poor clinicopathological parameters, advanced tumor stage, and reduced survival. Tumor behavior in the No. 7 group was similar to that in the D2 group, but poorer than in the D1 group in terms of advanced tumor stage, with 5-year survival rates of 34.3%, 25.9% and 54.6%, respectively. Five-year survival rates in the No. 7 group were comparable to those in the D2 group (P>0.05), but significantly lower than in the D1 group (P<0.05). Logistic multivariate regression analysis established No. 3 and 9 station LN metastasis, node classification, and tumor-node-metastasis stage as independent risk factors for No. 7 station LN metastasis. Thus, No. 7 station LNs should be ascribed to D2 lymphadenectomy in gastric cancer.