Effect of occult cancer screening on mortality in patients with unprovoked venous thromboembolism

Introduction: Unprovoked venous thromboembolism (VTE) may be the first manifestation of an underlying cancer. We aimed to determine whether extensive screening for occult cancer in patients with unprovoked VTE was effective in reducing overall mortality among VTE patients included in prospective cancer screening studies.

Methods: This pre-specified analysis of a systematic review and individual patient data meta-analysis included prospective studies comparing extensive screening with limited screening strategies for detection of occult malignant disease in unprovoked VTE patients. Overall mortality was calculated and compared according to the allocated screening strategies.

Results: Among 1830 included patients, occult cancer was detected either at screening or during a 2-year follow-up period in 98 (5.4%, 95% CI 4.4 to 6.5). Twenty-seven out of the 56 patients (48.2%) diagnosed with cancer in the extensive screening group died during follow-up as compared with 23 out of 42 patients (54.8%) in the limited screening group (HR, 0.83; 95% CI, 0.48-1.45). Subgroup analyses according to time of cancer diagnosis (i.e. at screening vs. during follow-up) and according to whether cancer was diagnosed by limited screening or more extensive testing yielded similar results.

Conclusion: In this individual patient data meta-analysis of clinical trials on limited vs. extensive screening, extensive screening for occult malignancy in patients with unprovoked VTE was not effective in reducing overall mortality. Diagnosing an occult cancer in unprovoked VTE patients was associated with a poor outcome.