Prevalence of Tumor Thrombus at RCC Diagnosis and Risk of Venous Thromboembolism

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In a Dutch single-institution retrospective cohort study reported in JACC: CardioOncology, Kaptein et al identified the prevalence of venous tumor thrombus at diagnosis in patients with renal cell carcinoma (RCC) and the associated risk of venous thromboembolism.

Study Details

The study included 647 consecutive patients diagnosed with RCC between January 2010 and December 2019 at Leiden University Medical Center. Patients were followed for 2 years after RCC diagnosis or until the occurrence of venous thromboembolism, arterial thromboembolism, major bleeding, or death.

Key Findings

Among 647 patients, 86 (13%) had venous tumor thrombus at RCC diagnosis. Of these, 34 were limited to the renal vein, 37 were located in the inferior vena cava below the diaphragm, and 15 extended above the diaphragm. Tumor thrombus at RCC diagnosis was associated with high tumor grade (odds ratio [OR] = 5.5, 95% confidence interval [CI] = 3.1–9.8), low Karnofsky performance status (OR = 2.5, 95% CI = 1.4–4.2) and distant metastases at RCC diagnosis (OR = 3.0, 95% CI = 1.9–4.7).

Among patients with tumor thrombus at diagnosis, thrombectomy alone was performed in 36 patients, thrombectomy was performed and anticoagulation treatment was given in 9, anticoagulation treatment alone was given in 15 (6 patients receiving anticoagulation were already receiving chronic anticoagulation for a different indication and continued their treatment), and 26 patients received no specific tumor thrombus treatment. 

During a median follow-up of 24 months (interquartile range = 7.0–24), 17 patients with tumor thrombus developed venous thromboembolism compared with 19 patients without tumor thrombus (adjusted hazard ratio [HR] = 6.6, 95% CI = 3.2–14). Risk of venous thromboembolism was higher among patients with tumor thrombus extending above the diaphragm vs those with tumor thrombus in the inferior vena cava below the diaphragm or limited to the renal vein.

In an analysis of 2-year cumulative outcomes including only patients with vs without tumor thrombus at RCC diagnosis, the rate of venous thromboembolism in those with vs without tumor thrombus was 22.0% vs 3.4%. In the tumor thrombus cohort, rates of venous thromboembolism were 27% among those receiving thrombectomy vs 17% among those not receiving thrombectomy (HR = 1.1, 95% CI = 0.41%–2.9%). Rates were 18% among those receiving anticoagulation for any therapeutic reason vs 24% among those not receiving anticoagulation (HR = 0.56, 95% CI = 0.13%–2.5%). Receipt of anticoagulation was associated with increased risk of major bleeding (32% vs 12%, HR = 3.4, 95% CI = 0.95%–12.0%).  

The investigators concluded, “Patients with RCC-associated [tumor thrombus] were at high risk of developing [venous thromboembolism]. Future studies should establish which of these patients benefit from anticoagulation therapy.”

Frederikus A. Klok, MD, PhD, and Fleur H.J. Kaptein, MD, of the Department of Medicine–Thrombosis and Hemostasis, Leiden University Medical Center, are the corresponding authors for the JACC: CardioOncology article.

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