Tumor thrombus is a unique characteristic of renal cell carcinoma (RCC). However, only a few studies have reported its clinical influence on the occurrence of venous thromboembolism (VTE). This study aimed to clarify the influence of tumor thrombus and other risk factors for VTE and to elucidate the impact of tumor thrombus on survival outcomes. We retrospectively reviewed data from patients with RCC who underwent radical or partial nephrectomy from September 1999 to August 2015 at Seoul National University Hospital. A total of 2762 patients were enrolled. The 1- and 5-year cumulative incidences of VTE were 0.5% ± 0.1% and 1.5% ± 0.3%, respectively. During a median follow-up of 39.0 months (95% confidence interval [CI], 37.1-41.0 months), deep vein thrombosis occurred in 13 patients and pulmonary embolism in 15 patients. Patients with tumor thrombus (diagnosed by surgical pathology findings) had a significantly higher incidence of VTE than those without thrombus (odds radio 8.160, 95% CI, 1.480-45.004). Older age (≥60 years) and higher preoperative C-reactive protein (>0.5 mg/dL) were also significant risk factors for VTE. Additionally, tumor thrombus was independently associated with worse progression-free survival (PFS) but not with overall survival (OS) in multivariable analysis (hazard ratio [HR] 1.916, 95% CI, 1.295-2.834 for PFS; HR 1.164, 95% CI, 0.755-1.793 for OS). In conclusion, the incidence of VTE was relatively low in patients who underwent surgery for RCC. Nevertheless, patients with tumor thrombus had an increased risk of VTE and should be closely monitored for VTE.
Keywords: renal cell carcinoma; risk factors; surgery; survival; venous thromboembolism.