Screening for Occult Malignancy in Patients With Idiopathic Venous Thromboembolism

Overview

Blood clots in leg veins (deep vein thrombosis) or lung arteries (pulmonary embolism) that happen for no reason (i.e. unexplained) are both called "unprovoked venous thromboembolism" (VTE). These unexplained blood clots can be the first symptom of cancer. Up to 10% of patients with unexplained blood clots will be diagnosed with cancer within one year of their blood clot diagnosis. These cancers can be found anywhere in the body although the relationship appears stronger with the pancreas, ovary and liver. Cancer testing in patients with blood clots is controversial. There is presently a wide variety of expert opinions and practices. Previous studies showed that a limited cancer screen including a medical history, physical examination, basic blood work and chest X-ray, will find about 90% of cancers. More recent and better designed studies showed that the limited cancer screen misses many cancers and needs to be improved. More extensive cancer testing may find more cancers but is potentially uncomfortable for patients, costs a lot of money and involves a lot of people. The "comprehensive computed tomography" is less uncomfortable, inexpensive, radiological test made to find many cancers at once. Thus, the scientific question to be asked is: Does a "comprehensive computed tomography" miss less cancers than a limited cancer screen in patients with blood clots? The main goal of this study is to find out if a "comprehensive computed tomography" misses less cancers than a limited cancer screen in patients with unexplained blood clots. The second goal of the study is 1) to find out if a "comprehensive computed tomography" finds more "curable" cancers than the limited cancer screen; 2) to find out if the patients diagnosed with cancer are still alive and cancer-free after one year (i.e. the patients with curable cancer were treated and are doing well); 3) to prove that a negative "comprehensive computed tomography" means that the patient will not have cancer and; 4) to find out if a "comprehensive computed tomography" is well tolerated and safe for patients.