title: Screening for occult malignancy with FDG-PET/CT in patients with unprovoked venous thromboembolism.
abstract: 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 20,711€ 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.
authors.affiliation: Hematology Service, Clínica Universidad de Navarra, Pamplona, Spain.
authors.forename: Ana
authors.initials: A
authors.lastname: Alfonso
authors.forename: Margarita
authors.initials: M
authors.lastname: Redondo
authors.forename: Tomás
authors.initials: T
authors.lastname: Rubio
authors.forename: Beatriz
authors.initials: B
authors.lastname: Del Olmo
authors.forename: Pablo
authors.initials: P
authors.lastname: Rodríguez-Wilhelmi
authors.forename: María J
authors.initials: MJ
authors.lastname: García-Velloso
authors.forename: José A
authors.initials: JA
authors.lastname: Richter
authors.forename: José A
authors.initials: JA
authors.lastname: Páramo
authors.forename: Ramón
authors.initials: R
authors.lastname: Lecumberri
mesh_terms: D000368:Aged; D000925:Anticoagulants / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000097:blood; D001779:Blood Coagulation Factors / Q000032:analysis*; D055088:Early Detection of Cancer; D005260:Female; D019788:Fluorodeoxyglucose F18; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009382:Neoplasms, Unknown Primary / Q000175:diagnosis* / Q000209:etiology / Q000378:metabolism; D049268:Positron-Emission Tomography; D011379:Prognosis; D011446:Prospective Studies; D019275:Radiopharmaceuticals; D014057:Tomography, X-Ray Computed; D054556:Venous Thromboembolism / Q000150:complications* / Q000188:drug therapy
chemical_list: D000925:Anticoagulants; D014408:Biomarkers, Tumor; D001779:Blood Coagulation Factors; D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: FDG-PET/CT; occult cancer; screening; tissue factor; venous thromboembolism