Risk Factors for Para-Aortic Lymph Node Metastasis in Esophagogastric Junction Cancer: Results from a Prospective Nationwide Multicenter Study

Background: Several studies have reported a high incidence of metastasis to para-aortic station 16a2lat (no. 16a2lat) among patients with esophagogastric junction (EGJ) cancer. However, the risk factors for no. 16a2lat metastasis are unclear. This study aimed to clarify the risk factors for no. 16a2lat metastasis in patients with EGJ cancer. Methods: Among 371 prospectively enrolled patients with EGJ cancer, 344 patients who underwent no. 16a2lat lymph node dissection were analyzed. Background factors were compared between the patients with and those without no. 16a2lat metastasis. The association between the histologic status of 10 regional lymph node stations and that of no. 16a2lat metastasis was evaluated. Results: Among the background factors, clinical N2–3 was the only independent risk factor for no. 16a2lat metastasis (odds ratio [OR], 5.90; p = 0.003). The metastasis rate of no. 16a2lat was 11.8% (11/93) for the patients with cN2–3 disease and 2.0% (5/251) for those with cN0–1 disease. The multivariate analysis showed that nos. 2 and 7 metastases were independent risk factors for no. 16a2lat metastasis, with respective ORs of 5.53 (p = 0.018) and 4.00 (p = 0.041). The patients with neither station no. 2 nor no. 7 metastasis did not exhibit no. 16a2lat metastasis, whereas the rate of no. 16a2lat metastasis was 23.7% for the patients with metastases of both stations. Conclusions: Clinical N2–3 and histologic positivity of station nos. 2 and 7 were independent risk factors for no. 16a2lat metastasis. These findings could potentially assist in determining the indication for no. 16a2lat dissection for patients with EGJ cancer.