Clinicopathologic factors correlated with number of metastatic lymph nodes in oesophageal cancer.

Abstract

The number of metastatic lymph nodes is applied to the staging system of gastric cancer and colorectal cancer. However, it has not been evaluated in oesophageal cancer. Of 258 patients with primary squamous cell carcinoma of the thoracic oesophagus between February 1981 and December 1999, 160 underwent three-field oesophagectomy with a curative intent. Clinicopathologic characteristics of those 160 patients were retrospectively investigated according to the number of metastatic lymph nodes. Seventy-eight patients had no lymph node metastases and 82 (51.3%) had lymph node metastases; 51 [31.9%)] had between 1 and 4 positive lymph nodes, and 31 (19.4%) had > or =5. The number of metastatic lymph nodes was significantly correlated with tumour size, macroscopic classification, histological differentiation, pT, pN, and vessel invasions. Multivariate analysis showed that lymph vessel invasion (relative risk 12.6), histological differentiation (relative risk 4.2), and tumour size (relative risk 3.8) were independent factors correlated with number of metastatic lymph nodes. The number of metastatic lymph nodes was also well correlated with the Japanese nodal level and TNM stage, respectively (p<0.001). The 5-year disease-specific survival rate according to the number of positive lymph nodes was 90% for patients without lymph node metastases, 52.2% with 1-4, and 28.9% with > or =5, respectively, p<0. 0001; 0 vs 1-4, p<0.05; 1-4 vs > or =5). The number of positive lymph nodes is well correlated with tumour progression and provides a useful prognostic indicator after oesophagectomy for oesophageal cancer.