Objectives
We retrospectively examined the venous thromboembolism (VTE) events diagnosed in the Prophylaxis of High‐Risk Ambulatory Cancer Patients Study (PHACS), a multi‐center randomized trial, to assess the value of screening vascular imaging for the diagnosis of incidental VTE in high‐risk cancer patients.
Methods
A total of 117 asymptomatic cancer patients with a Khorana score ≥3 starting a new systemic chemotherapy regimen were enrolled in a prospective randomized control trial. Patients underwent baseline venous ultrasound (US) of the lower extremities (LEs) and screening contrast‐enhanced chest computed tomography (CT). Those without preexisting VTE were then randomized into observation or dalteparin prophylaxis groups and were screened with serial US every 4 weeks for up to 12 weeks and imaged with contrast‐enhanced chest CT at 12 weeks. Any additional imaging performed during the study period was also evaluated for VTE.
Results
Baseline prevalence of incidental VTE was 9% (n = 10) with 58% percent of VTEs diagnosed by screening US. Incidence of VTE in the randomized phase of the trial was 16% (n = 16) with 21% (n = 10) of patients in the control arm and 12% (n = 6) of patients in the dalteparin arm developing VTE, a non‐significant 9% absolute risk reduction (HR = 0.69, 95% CI 0.23–1.89). Sixty‐nine percent of these patients were asymptomatic with 31% of patients diagnosed by screening US.
Conclusions
Adding screening US to routine oncologic surveillance CT in high‐risk ambulatory cancer patients with a Khorana score ≥3 can lead to increased VTE detection, with potential for decreased morbidity, mortality, and health care spending.