Abstract Number: OC 16.3
Meeting: ISTH 2022 Congress
Background: Risk of VTE is 4-7 fold higher in cancer pts. Little is known about the risk of VTE in patients with melanoma on ICI compared to chemotherapy.
Aims: We assessed the incidence and risk factors of VTE in melanoma pts on ICI and/or chemotherapy.
Methods: We conducted a cohort study using SEER-Medicare database to evaluate VTE in pts treated from 2008-2019 with ICI (ipilimumab, nivolumab, pembrolizumab) and/or chemotherapy within 2 years of treatment initiation. VTE of deep venous thrombosis and pulmonary embolism were identified by at least two outpatient claims or one inpatient claim. Clinical risk factors of VTE were evaluated by time-varying Cox analysis.
Results: The cohort comprised 14,456 pts with median age 75 (24-101) years and 68.3% male. Of these, 8.0% received ICI, 69.5% chemotherapy, and 22.5% chemotherapy+ICI. Most had hypertension (72%), 36.4% had prior cerebrovascular disease, and 18% had atrial fibrillation. 11.1% were on anticoagulation. Incidence rates of VTE after treatment start are shown (Figure 1). VTE was highest at 3 months after starting therapy with 25 events per 100 person-years in those receiving chemotherapy+ICI, 22 events with ICI alone and 19 events with chemotherapy alone.
In multivariate analysis, prior history of VTE and hypertension were associated with increased risk of VTE (HR 2.88 [95% CI, 2.54-3.26] and HR 1.29 [95%CI, 1.14-1.46], respectively). Treatment with chemotherapy+ICI was associated with increased risk of VTE (HR 1.42 [95%CI, 1.26-1.59]) over chemotherapy alone (Figure 2). Treatment with ICI alone was associated with similar risk of VTE as chemotherapy alone (HR 1.08 [95%CI, 0.91-1.29]).
Conclusion(s): Highest rates of VTE were observed in pts receiving both ICI and chemotherapy and in the first 3-12 months after starting therapy. Risk factors include history of VTE, hypertension, and treatment with both chemotherapy+ICI. Further studies are needed to identify benefit of thromboprophylaxis.
To cite this abstract in AMA style:Sussman T, Vu L, Markt S, Koroukian S, Khorana A. Increased Rate and Risk Factors of Venous Thromboembolism (VTE) in Older Patients (pts) with Melanoma Receiving Chemotherapy and/or Immune Checkpoint Inhibitors (ICI): a SEER-Medicare Analysis [abstract]. https://abstracts.isth.org/abstract/increased-rate-and-risk-factors-of-venous-thromboembolism-vte-in-older-patients-pts-with-melanoma-receiving-chemotherapy-and-or-immune-checkpoint-inhibitors-ici-a-seer-medicare-analysis/. Accessed October 2, 2023.
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