Presence of varicose veins in cancer patients increases the risk for occurrence of venous thromboembolism

Summary Background Cancer patients are at increased risk of venous thromboembolism (VTE). Objective We investigated the association of a history of VTE, superficial thrombophlebitis, or the presence of varicose veins with the occurrence of VTE during the course of cancer. Methods Cancer patients were recruited in a prospective cohort study, the Vienna Cancer and Thrombosis Study. Patients who had VTE within 3 months before study inclusion were excluded. At study inclusion, history of VTE, history of superficial thrombophlebitis, and presence of varicose veins were recorded. Primary end point was the occurrence of symptomatic VTE. Hazard ratios were obtained using the competing risk analysis according to Fine and Gray. Results The cohort consisted of 1270 patients followed over a median of 590 days. A history of VTE was found in 66 patients (5.2%), superficial thrombophlebitis in 79 patients (6.2%), and varicose veins in 160 patients (12.6%). Ninety‐eight patients (7.7%) developed VTE during follow‐up. The hazard ratios for the risk of VTE in patients with a history of VTE or superficial thrombophlebitis were 1.44 (95% confidence interval: 0.67–3.07) and 1.94 (1.04–3.61), respectively, and 2.01 (1.26–3.21) in those with varicose veins. In multivariable analysis including history of VTE, history of superficial thrombophlebitis, presence of varicose veins, and other patient‐related factors, the presence of varicose veins (2.10 [1.29–3.41]) remained significantly associated with an increased risk of VTE. Conclusion The presence of varicose veins is associated with an elevated risk of VTE in cancer patients. This clinical parameter could be useful for individual risk assessment of VTE in these patients.