Background: There is a known relationship between venous thromboembolism and cancer, but there is no consensus as to how extensive screening for occult cancer should be in cases of venous thromboembolism with no apparent risk factor (idiopathic venous thromboembolism). The aim of this study was to investigate the extent to which limited screening of patients with idiopathic venous thromboembolism reveals occult cancer.
Material and method: The incidence of cancer during the first year after thrombosis was surveyed retrospectively for all patients with idiopathic venous thromboembolism at Bærum Hospital in the period 1.1. 2003-31.12. 2008. During this period, limited malignancy screening was performed routinely in cases of idiopathic venous thromboembolism, and we investigated the degree to which limited screening had indicated the possible presence of cancer.
Results: Of 974 patients with venous thromboembolism, 499 had idiopathic venous thromboembolism. Malignancy was detected in 47 of these (9.4%; 95% CI 7.1-12.3) during the first year after the thrombosis. Limited screening detected 44 of these 47 cases (94%) and had a negative predictive value of 99%. Limited screening found anomalies in 98 patients (20%) in whom malignancy was not detected.
Interpretation: Malignancy was detected in almost 10% of the patients with idiopathic venous thromboembolism in the course of the first year. Limited screening for occult malignancy identified the great majority of cases.