Determining Candidate D-dimer Thresholds for Lower-extremity Ultrasound in Monitoring Deep Vein Thrombosis in...

Ramucirumab (RAM) is administered either alone or in combination with paclitaxel (PTX) to treat advanced or recurrent gastric cancer. Patients receiving RAM may develop venous thromboembolism (VTE) and require close monitoring. We aimed to identify a practical D-dimer threshold for determining when to perform lower-extremity ultrasonography in patients with advanced or recurrent gastric cancer receiving chemotherapy, including RAM.

This retrospective study included 112 of 162 patients with advanced or recurrent gastric cancer who received RAM at Ogaki Municipal Hospital (Ogaki, Japan) between July 2015 and February 2024. Patient characteristics, D-dimer trends, ultrasonography use, and the number of VTE events were assessed. The D-dimer cutoff was estimated using receiver operating characteristic (ROC) analysis in a subset of patients who underwent ultrasonography for suspected VTE.

Of the treatment regimens, 106 patients received RAM plus PTX, and six received RAM alone. VTE occurred in three patients (2.6%) during the treatment period. A total of 53 lower-extremity ultrasonography examinations were performed to evaluate suspected deep vein thrombosis (DVT). The ROC-derived candidate D-dimer cutoff for predicting VTE was 4.4 μg/ml [area under the curve (AUC)=0.853; 95% confidence interval (CI)=0.479-1.000].

This exploratory study suggests that a D-dimer level ≥4.4 μg/ml may serve as a candidate indicator for determining the need for lower-extremity ultrasonography in RAM-treated patients with gastric cancer. However, the small number of VTE events and the selective nature of the ROC cohort limit the generalizability. Validation in larger studies is needed.