review of literature on clinical pancreatology - The Pancreapedia

clearly have a very high incidence <strong>of</strong> VTE soon after they undergo any invasiveneurosurgical procedure. Active chemotherapy, the use <strong>of</strong> erythropoetin agents, and the use<strong>of</strong> certain anti-cancer therapies such as thalidomide, high-dose steroids, and anti-angiogenictherapy also increase the risk <strong>of</strong> thrombosis. Similar to patients without cancer, the risk <strong>of</strong>venous thromboembolism is higher in patients with coexisting chronic medical illnesses.Development <strong>of</strong> VTE is clearly associated with decreased survival and this effect is greateramong patients initially diagnosed with local or regional stage cancer compared to patientswith metastatic cancer [453].Venous thrombosis with and without pulmonary embolism is a frequent complication <strong>of</strong>malignancies and second among the causes <strong>of</strong> death in tumor patients. Its incidence isreported to be 10 to 15 percent. Since for methodological reasons, this rate can be assumedto be too low and to disregard asymptomatic venous thrombosis, a combined retrospectiveand prospective study was performed to examine the actual frequency <strong>of</strong> venous thrombosisin tumor patients. The histories <strong>of</strong> 409 patients with different tumors, consecutively enrolledin the order <strong>of</strong> their altogether 426 inpatient treatments, were checked in retrospect for thefrequency <strong>of</strong> venous thrombosis and pulmonary embolism. Subsequently, 97 tumorinpatients were systematically screened, by means <strong>of</strong> duplex sonography and/orvenography, for venous thromboses in the veins <strong>of</strong> the pelvis and both legs. In theretrospective analysis, where no systematic screening for thromboses was performed andonly symptomatic thrombosis was recorded, venous thrombosis was found in 6.6 percent <strong>of</strong>all tumor patients, whereas in the prospective examination with systematic duplexsonography and / or venography <strong>of</strong> all patients, the percentage was 33 percent. In theprospective study, 31 percent <strong>of</strong> venous thromboses were symptomatic and 69 percentasymptomatic. In 39 percent <strong>of</strong> the cases in the retrospective analysis and 25 percent in theprospective analysis, venous thrombosis occurred during chemotherapy, surgery or radiationtherapy. Venous thrombosis was most <strong>of</strong>ten seen in metastasizing tumors and in colorectalcarcinoma (40 %), haematological system diseases (29 %), gastric cancer (30 %), bronchial,pancreas and ovarian carcinoma (29 %), and carcinoma <strong>of</strong> the prostate (17 %). It wasconcluded that regular screening for thrombosis is indicated even in asymptomatic tumorpatients because asymptomatic venous thrombosis is frequent, can lead to pulmonaryembolism and has to be treated like symptomatic venous thrombosis. This is particularly truefor metastasization during chemotherapy, surgical interventions, or radiation [454].Cancer is the most important acquired but <strong>of</strong>ten overlooked risk factor for the development <strong>of</strong>venous thromboembolism (VTE). Tumors can express procoagulant proteins, for example,and tumor masses may compromise venous blood flow by extrinsic compression <strong>of</strong> adjacentvessels. Cancers can also induce the production <strong>of</strong> inflammatory cytokines that indirectlycontribute to the development <strong>of</strong> hypercoagulability and the risk <strong>of</strong> thromboembolism.Additional risk factors for VTE experienced by patients with cancer include immobilization,because <strong>of</strong> cancer or its treatment, and the potential presence <strong>of</strong> thrombophilic geneticfactors. Many common therapeutic modalities also increase VTE risk, including surgery,chemotherapy agents, adjuvant hormonal manipulation, the use <strong>of</strong> angiogenesis inhibitors,and the presence <strong>of</strong> central venous access devices. The risk <strong>of</strong> VTE seems to be greaterwith certain tumor types, such as cancers <strong>of</strong> the pancreas, kidney, or brain. The value <strong>of</strong>extensive screening <strong>of</strong> patients with the first episode <strong>of</strong> idiopathic thromboembolism for thepresence <strong>of</strong> an occult malignancy remains debatable at this time. VTE continues to pose asubstantial risk to patients with cancer because <strong>of</strong> a variety <strong>of</strong> tumor-, host-, and therapyrelatedfactors [455].Venous thromboembolism (VTE) is a well-recognized and relatively frequent complication <strong>of</strong>malignancy, whereas tumor thrombosis is a rare complication <strong>of</strong> solid cancers. The correctdiagnosis <strong>of</strong> tumor thrombosis and its differentiation from VTE can alter patient managementand prevent unnecessary long-term anticoagulation treatment. To evaluate the contribution<strong>of</strong> 18 F-fluorodeoxyglucose positron emission tomography (PET)/computed tomography to the