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

Abstract

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.

Keywords: Gastric cancer; clinicopathological features; left gastric artery; lymph nodes; survival.

Figure 1

Kaplan-Meier survival curves for patients with gastric cancer according to the status of the No. 7 station lymph nodes (LNs). Differences in the survival rates among the three different subgroups were considered statistically significant (P<0.001).

Figure 2

Comparison of the overall survival rate among four subgroups comprising N0, D1, No. 7, and D2 patients. Differences in survival rates among the groupings were considered statistically significant (P<0.001). Survival curves were constructed using the Kaplan-Meier method.

Figure 3

Comparison of overall survival rates between D1 and No. 7 patients. Differences in survival rates between the two subgroupings were considered statistically significant (P<0.001). Survival curves were constructed using the Kaplan-Meier method.

Figure 4

Comparison of overall survival rates between D2 and No. 7 patients. Differences in the survival rates between the two subgroupings were considered no statistically significant (P>0.05). Survival curves were constructed using the Kaplan-Meier method.