BACKGROUND: Tumor-induced coagulation is widely observed in cancer patients. Moreover, it is associated with tumorigenesis, tumor progression and metastasis, by creating a proliferative and proangiogenic microenvironment. Therefore, D-dimer, a fibrin degradation product, correlates with tumor prognosis in several cancer types.

OBJECTIVES: This study aims to investigate whether D-dimer levels can be a predictive and monitoring indicator for chemotherapy response in metastatic breast cancer (MBC) patients.

DESIGN: This was a prospective study.

METHODS: This study included two groups, 76 patients diagnosed with metastatic breast carcinoma and 25 patients with primary breast carcinoma. Plasma D-dimer levels were measured prospectively before chemotherapy initiation, and after the fourth treatment cycle in MBC patients. D-dimer levels before chemotherapy (D0) were analyzed using Receiver Operating Characteristic (ROC) curves to determine the optimal cut-off baseline values of D0, and to evaluate their discriminatory abilities in predicting response to chemotherapy.

RESULTS: In the preliminary response evaluation, the mean level of D-dimer significantly decreased by 0.65 μg/ml in patients with partial response patterns, and by 0.5 μg/ml in patients with stable disease. In the disease progression group, a marked increase was seen in D-dimer levels by 1.2 μg/ml. Analysis of ROC curves showed that D-dimer levels at D0 could discriminate the response to chemotherapy, whereas progressive disease rate correlated with higher levels of D-dimer.

CONCLUSION: D-dimer level in plasma is a useful predictive and monitoring marker of response to chemotherapy in metastatic breast cancer.