Screening for colorectal cancer (CRC) contributes by reducing the incidence of this disease and mortality. Colonoscopy is considered the gold standard for screening for these tumors. It is well know that deep vein thrombosis (DVT) is a common manifestation in patients with cancer and may appear as the first manifestation of the disease. This study aimed to examine the association between idiopathic DVT and CRC, and to check the necessity of screening for cancer in this population. This study retrospectively reviewed the medical charts of 17 patients with idiopathic DVT but no history of CRC and of asymptomatic patients who underwent colonoscopy to screen for CRC. The presence of malignancy, all adenocarcinomas, was identified in 23.53% of the tests. The examination showed changes in 52.04% of the patients, with diverticular disease of the colon being the most prevalent (17.65%), followed by rectal ulcer (11.76%). The sensitivity of the test was low (57.2%) but the high positive predictive value was high (80%). The results suggest there is an association between DVT and CRC and thus there is a need for screening for neoplasias in subjects with DVT without a clear etiology.
