Screening for occult malignancy with FDG-PET/CT in patients with unprovoked venous thromboembolism
Alfonso A, Redondo M, Rubio T, Del Olmo B, Rodríguez-Wilhelmi P, Velloso MJ, Richter JA, Páramo JA, Lecumberri R.
Hematology Service, Clínica Universidad de Navarra, Pamplona, Spain.
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, a non-invasive 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%), 6 of them at early stage. During follow-up 2 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 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 20,711€ to 11,670€. 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.
CITATION Int J Cancer. 2013 Apr 24. doi: 10.1002/ijc.28229