Metastatic characteristics of lymph node in cervical region and radiotherapy target volume after dissection of thoracic esophageal carcinoma

Objective To investigate the metastatic characterislics of cervical lymph node in thoracic esophageal cancer of two-field lymph node dissection after radical surgery and to provide evidence for postoperative radiotherapy. Methods Local-regional lymph node metastasis after surgery of 126 cases with esophageal squamous cell carcinoma from 2004 t0 2009 were reviewed. Boundaries of cervical lymph node were according to Som,s imaging-based nodal classification system. Enumeration data were compared by X2 test , and the risk factors of lymph node metastasis were analyzed with Logistic regressive model . Results Lymph node metastasis rate of cervical region was up t0 68. 3％ in all the cases with local-regional lymph node metastasis (86/126) , and lymph node metastasis rate in level I was higher than those in the other levels (43. 7％ , 55/126) . There was obvious difference in lymph node metastasis rate between the right and the left cervical region (53. 2％ vs 30. 2％ ,X2 = 13. 73 ,P = 0. 000). Moreover, the results also shown that lymph node metastasis rate was notably increased in levelⅠ ,Ⅱ and Ⅲa of the right compared with those of the left, showing statistical significance ( 43. 70％ : 15. 1％ , 17. 5％ : 7. 1 ％ , 17. 5％ : 5. 6％ , X2 = 24. 79,6. 22,8. 77 ,P =0. 000 ,0. 013 ,0. 003) . The sum of lymph node metastasis rate was 95％ ( 82/86) in pararecurrent nerve and medial jugular vein, and 85％ ( 73/86) in para-recurrent nerve. In addition,multivariate analysis showed that lymph node metastasis in level Ⅰ was high risk factor for lymph nodemetastasis of level Ⅱ . Conclusions Lymph node metastasis of cervical region mainly focused on pararecurrent nerve and medial jugular vein. Key words: Esophageal neoplasms/surgery; Neoplasms metastasis,neck lymph node; Radiotherapy target volume