Cervical lymph node metastasis classified as regional nodal staging in thoracic esophageal squamous cell carcinoma after radical esophagectomy and three-field lymph node dissection

BACKGROUND Lymph node metastasis (LNM) is most common in esophageal squamous cell carcinoma (SCC). The bi-directional spread is a key feature of LNM in patients with thoracic esophageal SCC (TE-SCC). The purpose of this study was to analyze the prognostic factors of survival in patients with TE-SCC with cervical lymph node metastasis (CLM) and validate the staging system of the current American Joint Committee on Cancer (AJCC) in a cohort of Chinese patients. METHODS Of 1715 patients with TE-SCC who underwent radical esophagectomy plus three-field lymph node dissection at a single hospital between January 1993 and March 2007, 547 patients who had pathologically confirmed CLM (296 had surgery only and 251 had surgery + postoperative radiotherapy) were included in this study. The locations of the lymph nodes (LNs) were classified based on the guidelines of the Japanese Society for Esophageal Diseases. RESULTS The rate of CLM was 31.9% for all patients and was 44.2%, 31.5%, and 14.4% for patients with upper, middle, and lower TE-SCC, respectively (P < 0.0001). The rates of metastasis to 101 (paraesophageal lymph nodes), 104 (supraclavicular lymph nodes), 102 (deep cervical lymph nodes) and 103 (retropharyngeal lymph nodes) areas were 89.0%, 25.6%, 3.7% and 0.5%, respectively. The 5-year overall survival (OS) rate with CLM was 27.7% (median survival, 27.5 months). The 5-year OS rates were 21.3% versus 34.2% (median survival, 21.9 months versus 35.4 months) for after surgery only versus surgery + postoperative radiotherapy, respectively (P < 0.0001 for both). Multivariate analysis showed that the independent prognostic factors for survival were sex, pT stage, pN stage, number of fields with positive LNs, and treatment modality. In surgery only group, the 5-year OS rates were 24.1%, 16.2% and 11.7%, respectively, when there was metastasis to 101 LN alone, 104 LN alone or both 101 LN and 104 LN. The 5-year OS rates were 17.7%, 22.5% and 31.7%, for patients with upper, middle and lower TE-SCC , respectively (P = 0.112). The 5-year OS rates were 43.0%, 25.5%, 10.2% in patients with 1 field (cervical LNs), 2 fields (cervical + mediastinal, and/or cervical + abdominal LNs), and 3 fields (cervical + mediastinal + abdominal LNs) positive LNs, respectively (P < 0.0001). The number of fields of positive LNs did not impact the OS according to different pN stage (all P > 0.05). CONCLUSION Patients with TE-SCC with CLM have better prognosis, which supports the current AJCC staging system for esophageal SCC.