Successful direct oral anticoagulant management of asymptomatic superior mesenteric vein thrombosis after adjuvant chemotherapy for colorectal cancer patient: A case report.

Owing to advances in cancer treatment and the diversification of treatment methods, cancer-associated thrombosis is increasing. Cancer can cause blood clots by activating the blood clotting system, increasing clotting factors through inflammation, reducing blood flow due to immobilization and damaging blood vessels through treatments such as chemotherapy. In clinical practice, superior mesenteric vein (SMV) thrombosis is occasionally observed in patients with cancer; however, certain cases of asymptomatic thrombosis can be serious. In the present case, a 71-year-old woman underwent laparoscopic high anterior resection for colorectal cancer. The patient received capecitabine as postoperative adjuvant chemotherapy for 6 months. Contrast-enhanced CT after the completion of chemotherapy revealed a sizable thrombus in the SMV. The thrombus occupied the SMV lumen without evident intestinal ischemia. D-dimer levels were elevated. Since the patient remained asymptomatic, edoxaban (30 mg/day) was administered in an outpatient setting. Six months later, contrast-enhanced CT confirmed thrombus resolution. No hemorrhagic events were observed during edoxaban treatment. In conclusion, cancer and chemotherapy are risk factors for thrombosis, indicating that regular D-dimer measurements may be necessary during cancer treatment. In addition, edoxaban may be an effective therapeutic tool for SMV thrombosis during chemotherapy for cancer.