Epidemiological Study Regarding the Incidence of Venous Thromboembolism in Patients After Cancer Remission

INTRODUCTION: The time course of reduction in the risk of venous thromboembolism (VTE) in patients who were diagnosed with cancer, treated with anticancer therapy, and in remission is unclear. We hypothesized that the risk of VTE will decrease over time after cancer remission. METHODS: We conducted a retrospective analysis using claims data for cancer remission in Japan. Background information of patients who developed VTE after cancer remission was collected, and the VTE incidence rate after cancer remission was analyzed. Subgroup analysis based on VTE history, cancer type, and the presence or absence of surgery during hospitalization was conducted. RESULTS: A total of 638,908 patients were eligible for the analysis. VTE occurred in 5533 of 638,908 cases, pulmonary embolism occurred in 779 cases, and deep vein thrombosis occurred in 5084 cases after cancer remission. The mean age of patients who developed VTE was 70.1 ± 12.5 years, and the proportion of men was 47.5%. All comorbidities and medications were higher in the VTE group (P < 0.001) than in the non-VTE group after cancer remission. The incidence of VTE was 2.4% per year in the first 30 days, 1.35% per year in 31–60 days, and gradually decreased to 0.48% per year in 181–360 days, becoming almost constant (annual rate 0.3%) 2 years after cancer remission. CONCLUSION: Risk of developing VTE decreased to the same level as that in patients without cancer 2 years after cancer remission. Although the guidelines do not specify the duration of anticoagulant prophylaxis for new onset or recurrent VTE after cancer remission and the appropriate duration of such prophylaxis may vary depending on VTE risk factors, determining the period of high risk of VTE for each patient and preventing VTE is considered important. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40119-022-00285-3.