OBJECTIVETo investigate the regularity of lymph node metastasis in cardiac carcinoma and its risk factors.

METHODComplete clinicopathological data of 768 cardiac carcinoma patients undergoing radical resection and lymph node dissection were collected. A retrospective cohort study was performed to analyze the distribution of lymph node metastasis (lymph node metastasis rate=number of patients with lymph node metastasis/number of patients with lymph node dissection; lymph node metastasis frequency=number of metastatic lymph node/number of total resected lymph node) and the influence of clinicopathological factors on lymph node metastasis.

RESULTSOf the 768 patients, 599 were male and 169 were female, with mean age of 61(28 to 85) years. According to gastric cancer staging criteria from the American Joint Cancer Association (AJCC) 7th edition in 2010, there was 256 cases in N0 stage, 171 cases in N1 stage, 181 cases in N2 stage, 160 cases in N3 phase; 18 cases in T1 stage, 30 cases in T2 stage, 9 cases in T3 stage, 711 cases in T4 stage. Borrmann type I( was found in 61 cases, type II( in 306 cases, type III( in 358 cases, type IIII( in 43 cases. The histological type was adenocarcinoma in 738 cases and signet ring cell carcinoma in 30 cases. A total of 9 183 lymph nodes were resected during operation for 768 patients with mean 12(0 to 57) nodes per case, while 510 patients were found to have 2 889 metastatic nodes; the lymph node metastasis rate was 66.4%(510/768), and lymph node metastasis frequency was 31.5%(2 889/9 183). Besides, 483 patients were found to have 2 759 metastatic lymph nodes and 8 246 resected lymph nodes in abdominal cavity with lymph node metastasis rate of 62.9%(483/768) and lymph node metastasis frequency of 33.5% (2 759/8 246); 57 patients were found to have 130 metastatic lymph nodes and 937 resected lymph nodes in thoracic cavity with lymph node metastasis rate of 7.4%(57/768) and lymph node metastasis frequency of 13.9%(130/937). Stations with the higher lymph node metastasis rate included paracardiac (left cardia: 38.8%, right cardia: 39.9%), lesser curvature of stomach(41.9%), left gastric artery (46%) and posterior pancreatic (38.5%). A total of 361 patients had resected lymph node number ≥12 during operation, while other 407 patients had number <12. Univariate analysis showed that Borrmann type, depth of tumor invasion and resected lymph node number were associated with lymph node metastasis. Lymph node metastasis rates of Borrmann type I(, II(, III( and IIII( patients were 55.7% (34/61), 62.7% (192/306), 73.7% (264/358) and 51.2%(22/43) respectively, and the difference was statistically significant (χ=18.115, P=0.000). Lymph node metastasis rates of T1, T2, T3, T4 stage patients were 0%(0/18), 30%(9/30), 100%(9/9) and 69.5%(494/711) respectively, and the difference was statistically significant (χ=63.971, P=0.000). Lymph node metastasis rate of patients with resected lymph node number ≥12 was 79.5%(287/361), which was significantly higher than 55.3%(225/407) of those with resected lymph node number <12(χ=50.496, P=0.000). Multivariate analysis revealed that higher T stage (OR=2.326, 95%CI: 1.758 to 3.078, P=0.000) and resected lymph node number ≥12(OR=2.998, 95%CI: 2.142 to 4.195, P=0.000) were independent risk factors of lymph node metastasis.

CONCLUSIONSThe lymph node metastasis rate of cardiac carcinoma is quite high. The metastasis occurs mainly in the surrounding of cardia, the small curvature of the stomach, the left artery of stomach and posterior pancreatic. The depth of tumor invasion and the number of lymph node dissection are independent risk factors of lymph node metastasis.