Patterns and influencing factors of lymph node metastasis of adenocarcinoma of the esophagogastric junction in 393 patients

Abstract

To explore the patterns and influencing factors of lymph node metastasis of adenocarcinoma of the esophagogastric junction (AEG). Clinicopathological data of 393 AEG patients who underwent radical resection and lymphadenectomy in the thoracic or abdominal cavity were collected. We analyzed the metastatic patterns of 5 119 excised lymph nodes with an average of 13 nodes per patient according to Siewert classification, and the associations between lymphatic metastasis and clinicopathological factors, such as tumor invasion, differentiation, maximum diameter, or pathological type were analyzed. The lymph node metastasis rate and ratio (LNR) were 70.0% (275/393) and 29.1% (1 492/5 119), respectively. All the Siewert subtypes of AEG mainly metastasize downwards to the abdominal lymph nodes, while also spread upwards to the mediastinal lymph nodes. Among them, the lymph node metastasis rate was highest in Siewert type Ⅰ and lowest in Siewert type Ⅲ AEG. The lymph node metastasis rate and ratio in T1, T2, T3, T4 AEGs were 0%, 29.4%, 75.0%, 74.6% and 0%, 10.1%, 14.2%, 32.0%, respectively (χ(2)=35.305, P<0.001 and χ(2)=134.034, P<0.001). The lymph node metastasis rate and ratio of the poorly differentiated adenocarcinoma were 36.0% and 79.3%, respectively, significantly higher than 22.1% and 61.7% of the well-differentiated adenocarcinoma (χ(2)=14.468, P<0.001 and χ(2)=120.009, P<0.001). The lymph node metastasis rate and ratio of patients with a tumor in maximum diameter ≥4 cm were 73.1% and 30.9%, significantly higher than 46.8% and 14.6%, respectively, in the patients with a tumor in maximum diameter of <4 cm (χ(2)=13.636, P<0.001 and χ(2)=64.767, P<0.001). The group of vascular tumor thrombus showed significantly higher lymph node metastasis rate and ratio than those in the group with no vascular tumor thrombus (84.6% versus 67.1%, χ(2)=7.946, P=0.005; and 45.0% versus 26.0%, χ(2)=112.723, P<0.001). The lymph node metastasis ratio of mucinous and signet ring cell adenocarcinoma was 34.9%, significantly higher than 28.5% of the adenocarcinoma (χ(2)=8.710, P<0.001) The depth of tumor invasion and degree of tumor differentiation were independent factors affecting lymph node metastasis (P=0.001 and P<0.001). The lymph node metastasis rate and ratio of AEG are high and influenced by many clinicopathological factors. The patterns of lymph node metastasis are different among different Siewert subtype AEGs.The depth of tumor invasion and differentiation degree are independent factors affecting lymphatic metastasis.