Does anticoagulation needed for distally located incidental pulmonary thromboembolism in patients with active cancer?

BACKGROUND: Incidental pulmonary embolism (IPE) is frequently detected in of cancer patients undergoing CT scans for staging work up or treatment response evaluation. Nevertheless, the optimal management of IPE remains unknown. Thus, we aimed to evaluate the clinical manifestations of IPE in cancer patients and to compare the clinical prognosis according to anticoagulation therapy. METHODS: We retrospectively analyzed medical records of cancer patients with newly diagnosed PE between March 2010 and December 2013. Baseline demographics, comorbidities, cancer status and clinical presentation of PE were recorded. We compared all cause death, recurrent venous thromboembolism and clinically relevant bleeding events in those with PE. Survival analysis was performed to assess effect of anticoagulation on IPE. RESULTS: Among 703 cancer patients diagnosed with PE, IPE was identified in 474 (67.3%) patients. Compared to symptomatic patients, those with IPE had more advanced malignancy, were more likely to be on current chemotherapy at the time of IPE diagnosis. These patients tend to have smaller embolic burden, as demonstrated by the lower rate of bilateral lung involvement and RV dysfunction. While symptomatic PE showed better survival with anticoagulation (median survival 6.0 vs. 17.3 months, p = 0.003), anticoagulation did not result in significant survival benefit in IPE (median survival 15.1 vs. 21.3, p = 0.225). However, in subgroup analysis, there was significant improvement in survival with anticoagulation in patients with proximal IPE (median survival 12.2 vs. 23.4 months, p = 0.023), but not in patients with distal IPE (21.2 vs. 15.1, p = 0.906). CONCLUSIONS: In cancer patients who were diagnosed with IPE, the overall survival was different according to the embolic burden and anticoagulation therapy.