E. A. Alore1, B. Johnson2, D. Mullikin3, J. Foster3, S. A. Vasudevan1,2, J. G. Nuchtern1,2, B. J. Naik-Mathuria1,2 1Baylor College Of Medicine,Department Of Surgery,Houston, TX, USA 2Texas Children’s Hospital,Department Of Pediatric Surgery,Houston, TX, USA 3Baylor College Of Medicine,Department Of Pediatrics, Section Of Hematology-Oncology,Houston, TX, USA
Introduction: Wilms tumor has the propensity for intracaval extension. The perioperative risk of pulmonary embolism is unknown and the necessity for use of anticoagulation is unclear.
Methods: We performed a retrospective, single institution review of children treated for Wilms tumor between 1999 and 2018. Patients with inferior vena cava (IVC) thrombus at diagnosis were identified and management, complications, and review of surveillance imaging was performed. Descriptive statistics were used for analysis.
Results: Of 170 patients with Wilms tumor, 13 (7.6%) had IVC tumor thrombus at diagnosis: 7 within the infrahepatic IVC, 2 extending to the intrahepatic IVC, and 4 extending into the right atrium. Ten of 13 patients (77%) received neoadjuvant chemotherapy, of whom 5 (50%) demonstrated decreased tumor thrombus size. Pre-operatively, one patient with extensive tumor thrombus into the right atrium was started on therapeutic low-molecular weight heparin, but developed a lower GI bleed requiring discontinuation of therapy. IVC thrombectomy with primary venous closure was performed for all patients, including retrieval of atrial thrombus for the extensive cases. Following operation, one patient received 81 mg aspirin for one month. Another patient (who did not receive antiplatelet or anticoagulant therapy) developed IVC vascular thrombus identified on surveillance ultrasound 1 week post-operatively. She was started on therapeutic low-molecular weight heparin for 3 months yet ultimately developed chronic IVC occlusion. The other 11 patients (85%) did not show evidence of vascular or tumor thrombus on cancer surveillance imaging following surgery (follow-up median 74 months, range 4-199 months). No patients developed a pulmonary embolism before or after surgery. All patients were alive at follow-up.
Conclusion: Anticoagulation does not appear to be warranted for Wilms tumor with intracaval extension as pulmonary embolism is unlikely. Following IVC thrombectomy, routine antiplatelet or anticoagulant treatment may be unnecessary as venous thrombosis is rare; however, surveillance imaging is important. Larger studies are required for validation.