The overarching objective of the study is to determine the effectiveness of LMWH/ warfarin vs. DOAC anticoagulation for preventing recurrent VTE in cancer patients. The investigators will conduct a trial of 940 cancer patients followed for 6 months. The intervention strategy is DOAC therapy with edoxaban, apixaban, rivaroxaban, or dabigatran. The comparator is LMWH alone or with warfarin. Within each arm, patients can choose the agent they prefer based on side effects, drug interactions, and practical issues such as co-pays. The trial compares these two strategies in terms of treatment: 1) benefits based on VTE recurrence; 2) harms based on bleeding rates; 3) burdens based on patients' reports of their experiences; and 4) mortality rates.