D-dimer cut-off value for predicting venous thromboembolism at the initial diagnosis in Japanese patients with advanced lung cancer

Objective Cancer is a well-known risk factor for venous thromboembolism. The D-dimer level is used to predict venous thromboembolism; however, reports on an appropriate D-dimer cut-off value in Japanese patients with advanced lung cancer are lacking. Therefore, this study aimed to calculate the D-dimer cut-off value for venous thromboembolism at the time of lung cancer diagnosis. Methods The Rising-venous thromboembolism/NEJ037 study was a multicenter, prospective observational study. Patients with lung cancer who were contraindicated for radical resection or radiation were enrolled and followed up for 2 years. In the present study (jRCT no. 061180025), a receiver operating characteristic curve for D-dimer levels was created using the dataset of the Rising-venous thromboembolism/NEJ037 study. Results The Rising-venous thromboembolism/NEJ037 study included a total of 1008 patients, of whom 976, whose D-dimer levels had been measured at the time of cancer diagnosis, were included in the present study. At the time of lung cancer diagnosis, 62 (6.3%) and 914 (93.7%) patients presented with and without venous thromboembolism, respectively. The D-dimer values ranged from 0.1 to 180.1 μg/ml and from 0.1 to 257.2 μg/ml in patients with and without venous thromboembolism, respectively. The receiver operating characteristic curve was discriminative with a cut-off value of 3.3 μg/ml and an area under the curve of 0.794 (sensitivity, 0.742; specificity, 0.782; 95% confidence interval, 0.725–0.863). Conclusions This is the first study to calculate the D-dimer cut-off value in Japanese patients with advanced lung cancer. Patients with D-dimer levels ≥3.3 μg/ml at the time of initial diagnosis may have coexisting venous thromboembolism.