A pilot study utilizing whole body 18 F-FDG-PET/CT as a comprehensive screening strategy for occult malignancy in patients with unprovoked venous thromboembolism

Abstract

Background: Approximately 7-10% of patients with unprovoked VTE will be diagnosed with cancer within 12 months. Although cancer screening has been proposed in these patients, the optimal strategy remains unclear. In a pilot study, we prospectively investigated the use of FDG-PET/CT to screen for occult malignancy in 40 patients with unprovoked VTE.

Materials/methods: Patients were initially screened for occult malignancy with a focused history, physical, and laboratory evaluation. Patients underwent whole body FDG-PET/CT and were followed for up to two years for a new diagnosis of cancer. The total costs of using FDG-PET/CT as a comprehensive screening strategy were determined using 2010 Medicare reimbursement rates.

Results: Completion of FDG-PET/CT imaging was feasible and identified abnormal findings requiring additional evaluations in 62.5% of patients. Occult malignancy was evident in only one patient (cancer incidence 2.5%) and FDG-PET/CT imaging excluded malignancy in the remainder of patients. No patients with a negative FDG-PET/CT were diagnosed with malignancy during an average (±SD) follow-up of 449 (±311) days. The use of FDG-PET/CT to screen for occult malignancy added $59,151 in total costs ($1,479 per patient). The majority of these costs were due to the cost of the FDG-PET/CT ($1,162 per patient or 78.5% of total per-patient costs).

Conclusions: FDG-PET/CT may have utility for excluding occult malignancy in patients with unprovoked VTE. The costs of this comprehensive screening strategy were comparable to other screening approaches. Larger studies are needed to further evaluate the utility and cost-effectiveness of FDG-PET/CT as a cancer screening strategy in patients with unprovoked VTE.

Fig. 1

Diagnostic evaluations performed to resolve findings on FDG-PET/CT.

Fig. 2

Left Panel. Transaxial fused 18 F-FDG PET/CT scan of the abdomen demonstrates a hypermetabolic mass in the head of the pancreas (arrow). At biopsy, pancreatic adenocarcinomas was demonstrated. Right Panel. Transaxial fused 18 F-FDG PET/CT scan of the abdomen demonstrates a large hypermetabolic lymph node (arrow) just inferior to the primary tumor in the head of the pancreas.