Warfarin is the most used anticoagulant worldwide and its anti-tumour potential has been demonstrated in different experimental cancer model systems.
In a Norwegian cohort study published in JAMA Internal Medicine (online, 6 November 2017), 1,256,725 individuals born between 1924 and 1954 were divided into two groups: warfarin users (92,942) and non-users (1,163,783)
. Warfarin users comprised individuals taking at least six months of a prescription with at least two years from first prescription to any cancer diagnosis.
After adjusting for age and sex, it was found that, compared with non-users, warfarin users had a significantly lower incidence of cancer in all sites (incidence rate ratio [IRR], 0.84; 95% confidence interval [CI], 0.82-0.86) as well as in prevalent organ-specific sites, such as lung (IRR, 0.80 [95% CI, 0.75-0.86); prostate (IRR, 0.69, 95% CI, 0.65-0.72] and breast (IRR 0.90; 95% CI, 0.82-1.00).
Warfarin use may have broad anticancer potential in individuals aged 50 years or older. This finding could have important implications for the selection of medications for patients needing anticoagulation, the authors concluded.