['Systemic activation of hemostasis and fibrolysis has been shown to be related to tumor progression in patients with malignancies such as lung cancer and colorectal cancer, but there has been no report of these clotting abnormalities in esophageal cancer. We investigated the clinical importance of measuring plasma levels of D-dimer (DD), which is a marker of the hypercoagulable stage, in preoperative patients with esophageal cancer.', 'Preoperative plasma DD levels were measured in 96 patients with primary esophageal cancer who were scheduled for esophagectomy with lymphadenectomy without preoperative treatment at our hospital. Results were correlated with the clinicopathological findings.', 'Significantly different plasma DD levels were found with respect to histologic T (p = 0.0015), histologic N (p < 0.0001), number of metastatic nodes (p < 0.0001), and histologic stages (p < 0.0001). The number of lymph node metastases (0/1 to 3/4 to 7/8-) was found to have the strongest association with DD level among the significant clinicopathologic factors (Spearman rank correlation 0.591, p < 0.0001). The most useful cut-off level of the plasma DD levels for diagnosis of lymph node metastasis was determined to be 0.4 microg/mL, with specificity and sensitivity for lymph node metastasis being 62.9% and 88.2%, respectively.'] Do plasma D-dimer levels show correlation with number of lymph node metastases in patients with esophageal cancer?