Risk of station 12a lymph node metastasis in patients with lower-third gastric cancer

BACKGROUND Controversy over the issue that No. 12a lymph node involvement is distant or regional metastasis remains, and the possible inclusion of 12a lymph nodes in D2 lymphadenectomy is unclear. As reported, gastric cancer (GC) located in the lower third is highly related to the metastasis of station 12a lymph nodes. AIM To investigate whether the clinicopathological factors and metastasis status of other perigastric nodes can predict station 12a lymph node metastasis and evaluate the prognostic significance of station 12a lymph node dissection in patients with lower-third GC. METHODS A total of 147 patients with lower-third GC who underwent D2 or D2+ lymphadenectomy, including station 12a lymph node dissection, were included in this retrospective study from June 2003 to March 2011. Survival prognoses were compared between patients with or without station 12a lymph node metastasis. Logistic regression analyses were used to clarify the association between station 12a lymph node metastasis and clinicopathological factors or metastasis status of other perigastric nodes. The metastasis status of each regional lymph node was evaluated to identify the possible predictors of station 12a lymph node metastasis. RESULTS Metastasis to station 12a lymph nodes was observed in 18 patients with lower-third GC, but not in 129 patients. The incidence of station 12a lymph node involvement was reported as 12.2% in patients with lower-third GC. The overall survival of patients without station 12a lymph node metastasis was significantly better than that of patients with station 12a metastasis (P < 0.001), which could also be seen in patients with or without extranodal soft tissue invasion. Station 12a lymph node metastasis and extranodal soft tissue invasion were identified as independent predictors of poor prognosis in patients with lower-third GC. Advanced pN stage was defined as independent risk factor significantly correlated with station 12a lymph node positivity. Station 3 lymph node staus was also proven to be significantly correlated with station 12a lymph node invovement. CONCLUSION Metastasis of station 12a lymph nodes could be considered an independent prognosis factor for patients with lower-third GC. The dissection of station 12a lymph nodes may not be ignored in D2 or D2+ lympliadenectomy due to difficulties in predicting station 12a lymph node metastasis.