Extensive screening for occult malignant disease in idiopathic venous thromboembolism: a prospective randomized clinical trial

Patients with symptomatic idiopathic venous thromboembolism and apparently cancer-free have an approximate 10% incidence of subsequent cancer. Apparently cancerfree patients with acute idiopathic venous thromboembolism were randomized to either the strategy of extensive screening for occult cancer or to no further testing. Patients had a 2-year follow-up period. Of the 201 patients, 99 were allocated to the extensive screening group and 102 to the control group. In 13 (13.1%) patients, the extensive screening identified occult cancer. In the extensive screening group, a single (1.0%) malignancy became apparent during follow-up, whereas in the control group a total of 10 (9.8%) malignancies became symptomatic [relative risk, 9.7 (95% CI, 1.3–36.8; P < 0.01]. Overall, malignancies identified in the extensive screening group were at an earlier stage and the mean delay to diagnosis was reduced from 11.6 to 1.0 months (P < 0.001). Cancer-related mortality during the 2 years follow-up period occurred in two (2.0%) of the 99 patients of the extensive screening group vs.four (3.9%) of the 102 control patients [absolute difference, 1.9% (95% CI, )5.5–10.9)]. Although early detection of occult cancers may be associated with improved treatment possibilities, it is uncertain whether this improves the prognosis