BACKGROUND: The objective of this study was to evaluate the prognostic relevance of subcarinal lymph node dissection in patients with esophageal squamous cell carcinoma (ESCC) and to identify a subset of patients in whom subcarinal lymph node dissection can be omitted. METHODS: We retrospectively analyzed 342 consecutive patients with thoracic ESCC who underwent R0 subtotal esophagectomy. All patients underwent subcarinal lymph node dissection. The efficacy index (frequency of metastasis to a particular lymph node station multiplied by the 5-year disease-specific survival rate of patients with metastasis to the station) was calculated for the subcarinal lymph node station, and the prognostic impact of dissecting this station was estimated with reference to the main tumor location. Independent predictive factors for pathological subcarinal lymph node metastasis were analyzed using a proportional hazards model. RESULTS: The overall frequency of metastasis to the subcarinal lymph nodes was 7.0 % (2.4, 8.9, and 5.8 % in patients with upper, middle, and lower thoracic ESCC, respectively). The efficacy index for the middle thoracic esophagus was 2.9, and that for the upper and lower thoracic esophagus was 0.0. The 5-year disease-free survival rate was significantly lower in patients with pathological subcarinal lymph node metastasis than those without (23.1 vs. 67.5 %, respectively; log-rank p < 0.0001). In multivariate analysis, clinical T stage (T2-T4) was the independent predictive factor for pathological subcarinal lymph node metastasis (p = 0.021). CONCLUSIONS: Subcarinal lymph node dissection might have little value in patients with upper and lower thoracic ESCC and could be omitted, especially for superficial carcinoma.
BACKGROUND: The objective of this study was to evaluate the prognostic relevance of subcarinal lymph node dissection in patients with esophageal squamous cell carcinoma (ESCC) and to identify a subset of patients in whom subcarinal lymph node dissection can be omitted. METHODS: We retrospectively analyzed 342 consecutive patients with thoracic ESCC who underwent R0 subtotal esophagectomy. All patients underwent subcarinal lymph node dissection. The efficacy index (frequency of metastasis to a particular lymph node station multiplied by the 5-year disease-specific survival rate of patients with metastasis to the station) was calculated for the subcarinal lymph node station, and the prognostic impact of dissecting this station was estimated with reference to the main tumor location. Independent predictive factors for pathological subcarinal lymph node metastasis were analyzed using a proportional hazards model. RESULTS: The overall frequency of metastasis to the subcarinal lymph nodes was 7.0 % (2.4, 8.9, and 5.8 % in patients with upper, middle, and lower thoracic ESCC, respectively). The efficacy index for the middle thoracic esophagus was 2.9, and that for the upper and lower thoracic esophagus was 0.0. The 5-year disease-free survival rate was significantly lower in patients with pathological subcarinal lymph node metastasis than those without (23.1 vs. 67.5 %, respectively; log-rank p < 0.0001). In multivariate analysis, clinical T stage (T2-T4) was the independent predictive factor for pathological subcarinal lymph node metastasis (p = 0.021). CONCLUSIONS: Subcarinal lymph node dissection might have little value in patients with upper and lower thoracic ESCC and could be omitted, especially for superficial carcinoma.