Preoperative plasma D-dimer predicts 1-year survival in colorectal cancer patients with absence of venous thromboembolism (VTE): a prospective clinical cohort study.

BACKGROUND: Fibrin formation is required for tumor angiogenesis, metastasis and invasion. Cancer discovered at the same time as or shortly after venous thromboembolism (VTE) tends to be advanced, and the prognosis poor. Previous studies have demonstrated that plasma D-dimer - a degradation product of cross-linked fibrin - correlates with tumor stage and prognosis in patients with colorectal cancer. However, it remains unclear whether D-dimer is of prognostic significance in colorectal cancer patients with absence of VTE.

OBJECTIVE: To examine whether the preoperative plasma D-dimer level predicts 1-year survival in pre- and postoperative VTE-negative colorectal cancer patients admitted for surgery.

METHODS: We measured preoperative D-dimer levels in 157 patients, and computed Kaplan-Meier survival curves according to the levels of D-dimer. Cox proportional-hazard regression analysis was used to compute hazard ratio as a measure of 1-year mortality rate ratio, controlling for potential confounding factors. The Aalborg Hospital's standard cut-off level of 0.3 mg L(-1) was used to distinguish negative and positive D-dimer results.

RESULTS: The overall 1-year survival rate was 87.3% (95% confidence interval (CI), 81.0-91.6%), with 78.1% survival (95% CI, 65.9-86.4%) in the positive D-dimer group compared with 93.6% survival (95% CI, 86.2-97.1%) in the negative D-dimer group. The adjusted hazard ratio of death in the positive D-dimer group compared with the negative D-dimer group was 3.6 (95% CI, 1.3-9.9).

CONCLUSION: A positive preoperative D-dimer is associated with a poor prognosis in colorectal cancer patients with absence of VTE.