背景：对于癌症患者中孤立性下肢深静脉血栓（DVT）的最佳抗凝治疗时长具有临床意义，但缺乏证据。长期的抗凝治疗可能对预防血栓事件有潜在益处，但也可能增加出血风险。方法：在日本的60家机构进行了一项多中心、开标、鉴定人盲、随机临床试验，随机将孤立性下肢DVT的癌症患者以1:1的比例分配到接受12个月或3个月的依诺沙班治疗组。主要终点是12个月内症状性复发性静脉血栓栓塞（VTE）或VTE相关死亡的综合终点。主要次要终点是根据国际血栓与止血学会的标准，12个月内的重度出血。主要假设是12个月的依诺沙班治疗在主要终点上优于3个月的依诺沙班治疗。 结果：从2019年4月至2022年6月，共有604名患者进行了随机分组，经排除3名撤回同意的患者，601名患者被纳入意向治疗人群：12个月依诺沙班组296名患者，3个月依诺沙班组305名患者。平均年龄为70.8岁，28%的患者为男性，20%的患者基线时伴有DVT症状。12个月依诺沙班组296名患者中有3人（1.0%）发生主要终点即症状性复发性VTE事件或VTE相关死亡，而3个月依诺沙班组305名患者中有22人（7.2%）发生。两组的比值比为0.13，95%CI为0.03到0.44。12个月依诺沙班组296名患者中有28人（9.5%）发生主要次要终点即重度出血，而3个月依诺沙班组305名患者中有22人（7.2%）发生。两组的比值比为1.34，95%CI为0.75到2.41。预先指定的亚组对主要终点的估计结果没有影响。结论：对于孤立性下肢DVT的癌症患者，12个月的依诺沙班治疗在症状性复发性VTE或VTE相关死亡的综合结局方面优于3个月的依诺沙班治疗。

Background: The optimal duration of anticoagulation therapy for isolated distal deep vein thrombosis (DVT) in patients with cancer is clinically relevant, but the evidence is lacking. The prolonged anticoagulation therapy could have a potential benefit for prevention of thrombotic events, however, it could also increase the risk of bleeding. Methods: In a multicenter, open-label, adjudicator-blinded, randomized clinical trial at 60 institutions in Japan, we randomly assigned cancer patients with isolated distal DVT, in a 1-to-1 ratio, to receive either a 12-month or 3-month edoxaban treatment. The primary endpoint was a composite of a symptomatic recurrent venous thromboembolism (VTE) or VTE-related death at 12 months. The major secondary endpoint was major bleeding at 12 months, according to the criteria of the International Society on Thrombosis and Hemostasis. The primary hypothesis was that a 12-month edoxaban treatment was superior to a 3-month edoxaban treatment with respect to the primary endpoint. Results: From April 2019 through June 2022, 604 patients were randomized, and after excluding 3 patients who withdrew consent, 601 patients were included in the intention-to-treat population: 296 patients in the 12-month edoxaban group and 305 patients in the 3-month edoxaban group. The mean age was 70.8 years, 28% of the patients were men, and 20% of the patients had symptoms of DVT at baseline. The primary endpoint of a symptomatic recurrent VTE event or VTE-related death occurred in 3 of the 296 patients (1.0%) in the 12-month edoxaban group and in 22 of the 305 (7.2%) in the 3-month edoxaban group (odds ratio, 0.13; 95% CI, 0.03 to 0.44). The major secondary endpoint of major bleeding occurred in 28 of the 296 patients (9.5%) in the 12-month edoxaban group and in 22 of the 305 (7.2%) in the 3-month edoxaban group (odds ratio, 1.34; 95% CI, 0.75 to 2.41). The prespecified subgroups did not affect the estimates on the primary endpoint. Conclusions: In cancer patients with isolated distal DVT, 12 months was superior to 3 months for an edoxaban treatment with respect to the composite outcome of a symptomatic recurrent VTE or VTE-related death.