Frequency and predictors of chemotherapy-associated venous thromboembolism: The prospective PREVENT study

Background: Our knowledge on the burden of symptomatic and asymptomatic venous thromboembolism (VTE) in patients with cancer undergoing chemotherapy is limited. The aim of our study was to prospectively investigate the frequency of symptomatic VTE and asymptomatic deep vein thrombosis of the lower limbs among cancer patients undergoing chemotherapy. Methods: We studied 231 patients (164 men) with pancreatic (N.=36), lung (N.=136), ovarian (N.=32) or prostate (N.=27) cancer receiving first line (N.=192, 83.1%) or adjuvant chemotherapy, followed-up for 3-6 months. Results: Some 17 patients were diagnosed with VTE, either asymptomatic detected on leg ultrasound (N.=7) or symptomatic (N.=10). The total frequency of VTE was 10.3% (17/165 with follow-up). Pancreatic cancer had the highest frequency of VTE (4/25, 16%) followed by ovarian (3/26, 11.5%) and lung cancer (10/94, 10.6%). There was no statistically significant difference in VTE rates among cancer types (P=0.36). VTE occurred more frequently in the presence of metastases (13/85, 15.3% vs. 4/80, 5.0%, for the remainder, P=0.03, OR 3.4). In the subgroup of patients receiving first line treatment, VTE occurred more frequently in patients with metastases (13/84, 15.5% vs. 2/53, 3.8%, for the remainder, P=0.033). In patients with pancreatic, lung or ovarian cancer receiving first line treatment, VTE occurred more frequently in patients with metastatic disease (19.1% vs. 4.0%, for the remainder, P=0.015). Conclusions: VTE occurrence in this real-world patient cohort was high, reaching almost 20% in certain groups, like those with disseminated pancreatic, lung or ovarian cancer receiving first-line chemotherapy. Furthermore, VTE occurs mostly as a symptomatic event, being likely a result of the prothrombotic state of malignancy.