Risk Factors of Deep Vein Thrombosis for Cancer Patients and Their Prognoses in the Japanese Population

Objective Deep vein thrombosis (DVT) occurring in cancer patients accounts for about 9.2% of deaths. Here we retrospectively analyzed patients who had been newly diagnosed with solid cancers over a 7-year period in the Japanese population. Patients or Materials We analyzed a series of 1,399 patients with solid cancers and suspected DVT treated at Ehime University Hospital. As controls, cancer patients with suspected DVT upon physical and hematological examinations and those in whom DVT had been not confirmed by detailed examination (echography and/or contrast-enhanced CT) were used. Several prognostic factors for DVT and non-DVT patients were extracted from the electronic medical record. Results From among the 1,399 patients, leaving 224 patients with DVT and 560 without DVT as controls. The median overall survival (OS) period was 5.87 years for patients with DVT and 6.81 years for patients without DVT (p=0.0014). Anemia and thrombocytopenia were found to be strong risk factors related to an increased incidence of DVT. Female cancer patients with DVT had a significantly worse outcome than those without DVT (p=0.028). Analysis of OS in patients with DVT associated with gynecological cancers following treatment with three different direct oral anticoagulants (DOACs; edoxaban, rivaroxaban, and apixaban) indicated that those treated with apixaban had a significantly worse outcome than those treated with the others (p=0.019). Conclusion Our findings suggest that patients with solid cancers, especially gynecological cancers, have a poorer prognosis if they also have anemia and a low platelet count. Furthermore, the choice of DOAC for treatment of DVT may impact the prognosis.