Screening for occult malignancy with FDG-PET/CT in patients with unprovoked venous thromboembolism

Extensive screening strategies to detect occult cancer in patients with unprovoked venous thromboembolism (VTE) are complex and no benefit in terms of survival has been reported. FDG-PET/CT (2-[F-18] fluoro-2-deoxy-D-glucose positron emission tomography combined with computed tomography), a noninvasive technique for the diagnosis and staging of malignancies, could be useful in this setting. Consecutive patients 50 years with a first unprovoked VTE episode were prospectively included. Screening with FDG-PET/CT was performed 3-4 weeks after the index event. If positive, appropriate diagnostic work-up was programmed. Clinical follow-up continued for 2 years. Blood samples were collected to assess coagulation biomarkers. FDG-PET/CT was negative in 68/99 patients (68.7%), while suspicious FDG uptake was detected in 31/99 patients (31.3%). Additional diagnostic work-up confirmed a malignancy in 7/31 patients (22.6%), with six of them at early stage. During follow-up, two patients with negative FDG-PET/CT were diagnosed with cancer. Sensitivity (S), positive (PPV) and negative predictive values (NPV) of FDG-PET/CT as single tool for the detection of occult malignancy were 77.8% (95% CI: 0.51-1), 22.6% (95% CI: 0.08-0.37) and 97.1% (95% CI: 0.93-1), respectively. Median tissue factor (TF) activity in patients with occult cancer was 5.38 pM vs. 2.40 pM in those without cancer (p = 0.03). Limitation of FDG-PET/CT screening to patients with TF activity > 2.8 pM would improve the PPV to 37.5% and reduce the costs of a single cancer diagnosis from 20,711Euro to 11,670Euro. FDG-PET/CT is feasible for the screening of occult cancer in patients with unprovoked VTE, showing high S and NPV. The addition of TF activity determination may be useful for patient selection. What's new? A venous thromboembolism (VTE) event can be the first clinical manifestation of an occult malignancy, and patients suffering from unprovoked VTE also present a higher incidence of new cancer diagnosis during the following years. Yet extensive screening strategies to detect occult cancer are complex and no benefit in terms of survival has been reported. This study demonstrates for the first time the feasibility of combining plasma TF activity determination and the non#x02010;invasive imaging technique FDG#x02010;PET/CT in the search of hidden cancer in patients with unprovoked VTE. This strategy presents high sensitivity and negative predictive value as well as reasonable costs.