RISK OF CANCER AFTER LOWER LIMB ARTERIAL THROMBOSIS: A POPULATION-BASED COHORT STUDYFree Access

Introduction

Background: It is well known that venous thromboembolism may be a marker of occult cancer, but the association between arterial thrombosis in the lower limb and cancer is poorly understood. We therefore examined the risk of cancer after a diagnosis of lower limb arterial thrombosis.

Methods: Using data from the Danish National Patient Registry covering all Danish hospitals, we identified all patients with first-time lower limb arterial thrombosis between 1994–2013. Cancer outcomes were ascertained using data from the Danish Cancer Registry. We computed standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) calculated as the observed number of cancers relative to the expected based on national incidence rates by sex, age, and calendar year.

Results: Among 7925 patients with lower limb arterial thrombosis, we observed 968 cancers. The risk of any cancer was 2.4% (95% CI: 2.1%–2.7%) after 6 months of follow-up increasing to 12.2% (95% CI: 11.8%–12.6%) after 20 years. During the first 6 months of follow-up, the SIR of any cancer was 3.16 (95% CI: 2.72–3.64). The SIR remained elevated during 6–12 months (1.49, 95% CI: 1.18–1.87) and beyond 12 months (1.19, 95% CI: 1.10–1.28). The strongest association was found for lung cancer (0–6 months risk=0.6%, 95% CI: 0.5%–0.7%; 0–6 months SIR=7.77, 95% CI: 5.75–10.27).

Conclusions: A diagnosis of lower limb arterial thrombosis is a marker of occult cancer, especially lung cancer.

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