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 5 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 20,711e to 11,670e. 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.Cancer patients have an increased risk of venous thromboembolism (VTE), either deep vein thrombosis (DVT) or pulmonary embolism (PE), through different mechanisms, including tumor-and treatment-induced hypercoagulability, endothelial damage (chemotherapy toxicity and use of venous catheters) or venous stasis due to bed rest or surgical immobilization.

Performance of 18F-fluorodesoxyglucose positron-emission tomography combined with low-dose computed tomography for cancer screening in patients with unprovoked venous thromboembolism

“…First, interpretation is difficult to standardize, and the threshold for positivity is not clearly defined. Our definition of a positive FDG-PET/CT is in line with previous studies on this topic [15–17]. However, such a definition led to highly variable proportions of positive FDG-PET/CT across studies, from 31% to 63%.…”

Splanchnic venous thrombosis is a marker of cancer and a prognostic factor for cancer survival

“…25,26 The most recent guideline by the United Kingdom National Institute for Health and Clinical Excellence (NICE CG144; 2012), recommends considering an abdomino-pelvic CT scan in patients aged over 40 years presenting with venous thromboembolism. 27 We speculate if abdominal CT or PET/CT scans should be mandatory in the diagnostic work-up in patients with SVT.…”

Utility of 18F-FDG-PET/CT in patients suspected of paraneoplastic neurological syndrome: importance of risk classification

“…Patients were classified in low (score 0-2), intermediate (score [3][4] and high (score 5-7) pre-test risk of PNS.…”

“…Its value has also been described in other situations involving occult malignancy, as in patients with unprovoked venous thromboembolism [4] or in the detection of a synchronous second primary tumor [5]. Besides, it is known the significant rate of malignancy in incidental uptakes of FDG in PET imaging [6][7][8].…”