Abstract
PURPOSE: To investigate the usefulness of plasma D-dimer level for monitoring the development of distant organ metastasis in colorectal cancer (CRC) patients after curative resection. PATIENTS AND METHODS: One hundred and seventy-eight CRC patients after curative resection were enrolled in the study. Ninety-two patients developed distant organ metastasis during follow-up (metachronous metastasis), and blood was collected on the day metastasis was confirmed. Eighty-six patients had no evidence of metastasis yet, and their blood samples were evaluated at last return visit. The levels of D-dimer, carcinoembryonic antigen (CEA), and lactate dehydrogenase (LDH) between two patient groups were compared. The agreement between D-dimer and CEA (or LDH) was examined. The receiver operator characteristic (ROC) curve was used to evaluate the performance of D-dimer, CEA, LDH, and their combination in detection of distant organ metastasis. RESULTS: The level of D-dimer in CRC patients with metachronous metastasis was higher than that in non-metastasis patients (P<0.0001). Agreement between D-dimer and CEA was fair (κ=0.416, P<0.0001). D-dimer had a larger area under ROC (AUC) (0.85) compared to CEA (0.72) or LDH (0.68). The specificity of D-dimer (73.3%) was lower than that of CEA (74.4%), but the sensitivity (88.0%) of D-dimer assay was superior to that of CEA assay (65.2%). LDH showed the lowest sensitivity (42.4%) and highest specificity (95.3%) among the three bio-markers. The sensitivity and negative predictive value (NPV) of a combination assay (either D-dimer elevation or CEA elevation) were 94.6% and 91.1%, respectively, and the specificity and positive predictive value of another combination assay (both D-dimer elevation and LDH elevation) were 97.7% and 94.9%, respectively. Parallel test of the three markers improved the sensitivity and NPV to 95.7% and 92.7%, respectively. CONCLUSION: Combining with CEA and/or LDH, D-dimer could be a useful surveillance marker for distant organ metastasis in CRC patients after curative resection.