Fluorodeoxyglucose (FDG)-Positron Emission Tomography (PET) in Cancer Associated Venothromboembolism

Venothromboembolic disease (VTE), which includes deep venous thrombosis (DVT) and pulmonary embolism (PE), is a severe health problem, effecting 1.5/1000 per year in the general population. In patients over 60 years of age, the incidence is 1/100 per year. Of the two million Americans per year who will develop VTE, one third will develop pulmonary embolism (PE). VTE is usually diagnosed by Doppler ultrasound or contrast venography when present in the extremities, VQ scan or pulmonary angiography when PE is present. However, there are many instances when the diagnosis of VTE by conventional modalities is limited. These include obesity, recent trauma or surgery, the presence of a mass, the presence of clot around central lines, and clot occurring in the abdomen and pelvis. Furthermore, the differentiation between new and old clot has evaded all diagnostic imaging modalities, and no existing modality allows for an accurate delineation of all sites of thrombus within the body. New approaches to the diagnostic imaging of VTE in complicated cases are needed. The first hypothesis of this project is that FDG PET/CT can be used to accurately diagnose the presence and extent of acute VTE, and that it will distinguish new clot from old. Approximately 20-25% of all new cases of venous thromboembolism occur in known cancer patients. The risk of VTE is 4-6 fold greater in patients with cancer as those without (8-12% vs. 2%, respectively, lifetime risk). In many cases, the development of VTE occurs as the first clinical sign of the cancer, even before it is diagnosed. Among patients presenting with acute VTE have no obvious cause (defined as "idiopathic" or "unprovoked", as opposed to "secondary" VTE), the literature reports that up to 20% (range of reported incidence 7-20%) may ultimately prove to have cancer, depending on the series and whether the thrombosis is unifocal or multifocal. Despite the substantial prevalence of occult cancer in patients presenting with idiopathic VTE, there are no current recommendations that these patients be screened for the presence of cancer. The second hypothesis of the project is that FDG PET/CT can accurately be used to screen for the presence of cancer in patients with unprovoked (idiopathic) acute VTE. Objectives: There are two specific objectives to test the hypotheses associated with this project: 1. To establish the sensitivity of FDG PET/CT in the diagnosis of acute VTE. 2. To perform a pilot project to aid in the design of a larger trial to define the incidence of occult cancer in patients rigorously selected for idiopathic (unprovoked) VTE, and to investigate the value of FDG PET in the early detection of occult cancer in this population.

Sex

All

Minimum age

18 Years

Inclusion Criteria:

1. Inclusion criteria will include documented acute DVT (+/-PE) by Doppler ultrasound or contrast venography.
2. Subjects will be eligible either with provoked or unprovoked DVT.
3. To meet the inclusion criteria, patients must be enrolled and the initial PET/CT scan performed within 2 weeks of initial onset of symptoms of VTE.

Exclusion Criteria:

1. Subjects less than 18 years of age,
2. Those who are unable to understand and provide signature informed consent
3. Pregnant subjects. Any female of childbearing age who has a uterus and functional ovaries will undergo a serum pregnancy test prior to inclusion. 4. Subjects with calf-only blood clot will be excluded, due to the fact that these cases are often complicated by venous stasis disease, post-phlebitic syndrome, and the presence of both acute and chronic clot, which may compromise interpretation.

• DERIVEDRondina MT, Lam UT, Pendleton RC, Kraiss LW, Wanner N, Zimmerman GA, Hoffman JM, Hanrahan C, Boucher K, Christian PE, Butterfield RI, Morton KA. (18)F-FDG PET in the evaluation of acuity of deep vein thrombosis. Clin Nucl Med. 2012 Dec;37(12):1139-45. doi: 10.1097/RLU.0b013e3182638934. PMID 23154470