Venous thromboembolism and cancer risk.

Cancer increases the risk of venous thromboembolism (VTE) and about 20 % of all VTE are associated with cancer. VTE can also be used as a marker for occult cancer. The objective was to examine the correlation between VTE and cancer regarding predictors for a subsequent cancer diagnosis. Patients treated for VTE between January 1st 2006 and December 31th 2011 were extracted from the Swedish national quality register AuriculA and crossmatched with the Swedish National Patient Register. In total 7854 patients corresponding to 14284 treatments years were examined. Primary VTE was found in 6451 patients, with 3936 first and 2515 recurrent VTE. There were 1403 patients with secondary VTE. After a first or recurrent primary VTE the incidence of cancer diagnose was high being 9.4-10.0 % the first year compared to 2.7-2.5 % during the second year. Cancer in the digestive organs was the most common type of cancer among those with first primary VTE with 19.2 % of diagnoses. In multivariable analysis age was found to increase the risk of cancer diagnosis after both first and recurrent primary VTE HR 1.02 (CI 1.02-1.03) and HR 1.02 (CI 1.01-1.03). For a first primary VTE anemia HR 2.13 (CI 1.48-3.08) and male sex HR 1.38 (CI 1.09-1.76) increased the risk while hypertension HR 0.74 (0.57-0.96), dementia HR 0.30 (CI 0.10-0.95) and history of major bleeding HR 0.52 (CI 0.28-0.97) reduced the risk of a subsequent cancer diagnosis. There is a substantial proportion of patients being diagnosed with cancer the first year after a primary VTE, anaemia and male sex confers an increased risk.