Increased Risk of Cancer-Associated Thrombosis in Patients With History of VTE

History of venous thromboembolism (VTE) is a significant risk factor for recurrence of thrombosis after cancer diagnosis, according to the results of a study presented by Sargam Kapoor, MBBS, of Alaska Native Medical Center in Anchorage, Alaska, at the virtual 62nd American Society of Hematology (ASH) Annual Meeting and Exposition.

“The Khorana Risk score is the most well-validated tool for ambulatory cancer patients receiving systemic chemotherapy…[and] we know that a history of VTE is a major risk factor for recurrent thrombosis in the general population,” said Dr Kapoor. “Select data have also shown that prior VTE is a significant risk factor for cancer-associated VTE after cancer surgery and/or chemotherapy. However, a history of VTE is not included in the Khorana Risk score.”

This rationale motivated the investigators to examine the effect of a history of VTE on VTE recurrence in patients with cancer. They conducted a retrospective cohort study of patients diagnosed with cancer using aggregated de-identified data from the Watson Health IBM Explorys database, which contains electronic medical records of more than 300 major hospitals in the United States.

Patients with a diagnosis of cancer and those with a history of VTE more than 1 year prior to a cancer diagnosis were included in the study. The team then identified patients who developed recurrent VTE within 180 days of a cancer diagnosis. The primary endpoint was the incidence of cancer-associated VTE (CVTE) in patients with prior history of VTE compared with patients without a history of VTE. Baseline patient and disease characteristics were also compared between the patient groups.

From the database, 4,314,260 patients with a cancer diagnosis were included in the study. Of those, 144,110 patients (3.3%) had a history of VTE more than 1 year before cancer diagnosis.

Overall, 204,720 patients had CVTE within 180 days, translating to a 4.74% incidence of CVTE. When these patients were categorized according to prior history of VTE more than 1 year before cancer diagnosis, the incidence of CVTE at 180 days was 10-fold higher in those with a prior history of VTE compared with those who had no prior history (36.9% vs 3.66%, respectively; odds ratio [OR], 15.5; 95% CI, 15.3-15.7; P <.0001).

In a multivariate analysis, independent predictors of CVTE were history of VTE (OR, 7.79; 95% CI, 7.67-7.92; P <.0001), body mass index of 35 or more (OR, 1.122; 95% CI, 1.10-1.14; P <.0001), hemoglobin less than 10 g/dL (OR, 1.21; 95% CI, 1.20-1.23; P <.0001), white blood cell count more than 11 x 10⁹/L (OR, 1.01; 95% CI, 1.00-1.03; P =.019), and platelet count more than 350 x 10⁹/L (OR, 1.14; 95% CI, 1.12-1.15; P <.0001).

When the data were stratified according to patient Khorana score and history vs no history of VTE, the 180-day incidence of VTE was 38.22% vs 4.28%, respectively, in those with a low score; 39.79% vs 7.04%, respectively, in those with an intermediate score; and 40.44% vs 9.96%, respectively, in those with a high score.

“In summary, history of VTE more than 1 year before the diagnosis of cancer independently increases the risk of cancer-associated VTE,” concluded Dr Kapoor. “This risk is highest in the first month after cancer diagnosis, which may be due to surgery and/or the initiation of systemic treatments.”

The investigators suggested that a history of VTE should be considered if Khorana score is low or intermediate, and that large prospective observational studies are needed to assess the effect of history of VTE on cancer thrombosis.

Read more of Hematology Advisor’s coverage of the ASH 2020 meeting by visiting the conference page.

Reference

Kapoor S, Opneja A, Gollamudi J, Nayak LV. Prior history of venous thromboembolism is a significant risk factor for recurrence of thrombosis after cancer diagnosis. Presented at: American Society of Hematology (ASH) 62nd Annual Meeting and Exposition; December 5-8, 2020. Abstract 442.