Incidence, risk factors, and outcomes of venous thromboembolism after oncologic surgery: A systematic review and meta-analysis

Background: The risk and prognosis of VTE associated with oncologic surgery need to be quantified to guide patient management. We aimed to examine the availability of data and to report the incidence of venous thromboembolism (VTE) in cancer patients after surgery, as well as the clinical outcomes of VTE following oncologic surgery. Methods: We searched multiple databases for terms related to VTE after oncologic surgery from inception to November 1, 2017. A random-effects meta-analysis was done to calculate the pooled incidence of VTE. Results: Of the 8611 citations identified, 136 studies including 1,481,659 patients met the eligibility criteria. The overall incidence of VTE was estimated to be 2.3% (95% CI 2.1-2.5). Bone and soft tissue cancer (10.6%, 95% CI 2.9-18.2) and lung cancer (8.1%, 95% CI 3.7-12.6) were associated with the highest and second highest risk of postoperative VTE, respectively. Age (standardized mean difference [SMD] = 0.46, 95% CI 0.40-0.53; I-2 = 93.8%), radiation (OR 1.29, 95% CI 1.03-1.62; I-2 = 34.6%), transfusion (OR 1.96, 95% CI 1.48-2.59; I-2 = 57.0%), and operative time (SMD = 1.12, 95% CI 1.07-1.16; I-2 = 100%) were possible risk factors for postoperative VTE. Patients with VTE versus those without had increased odds of all-cause fatal events (11.15, 95% CI 4.07-30.56; I-2 = 92.0%). Conclusions: The risk of VTE after oncologic surgery remains high, and this risk varied according to the cancer type, study region, surgical location, and thromboprophylactic strategy. VTE is associated with increased mortality at the early stage of cancer surgery.