Warfarin may have anti-tumor properties, and warfarin-use was associated with a reduced relative risk of all cancer types, according to a study published in JAMA Internal Medicine.1
There is a growing need to elucidate the impact of warfarin, which inhibits pathways necessary for oncogenesis, on cancer prevention.
For this population-based cohort study, researchers analyzed the health outcomes of 1,256,725 patients and separated them into warfarin- and non-warfarin-using subgroups. Researchers defined warfarin-use as at least 6 months of use as determined by prescription history and at least 2 years of use from the first prescription filled to disease diagnosis.
Of the enrolled patients, 7.4% were warfarin users and 92.6% were non-users; 10.6% of all patients in the cohort had cancer.
There was a significantly lower incidence rate ratio (IRR) for all cancer sites once adjusted for age and sex among patients using warfarin compared with non-users (IRR, 0.84; 95 %CI, 0.82-0.86), and for 3 of the 4 most prevalent cancer sites: 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).
A subgroup analysis of patients with atrial fibrillation or atrial flutter also revealed a lower IRR in all cancer sites (IRR, 0.62; 95% CI, 0.59-0.65), and for all 4 of the most prevalent cancer sites: lung (IRR, 0.39; 95% CI, 0.33-0.46), prostate (IRR; 0.60; 95% CI, 0.55-0.66), breast (IRR, 0.72; 95% CI, 0.59-0.87), and colon (IRR, 0.71; 95% CI, 0.63-0.81).
The authors concluded that these findings “may have important implications for choosing medications for patient who need anticoagulation. Further studies are warranted to fully elucidate the mechanisms underpinning these observations.”
- Haaland GS, Falk RS, Straume O, Lorens JB. Association of warfarin use with lower overall cancer incidence among patients older than 50 years. JAMA Intern Med. 2017 Nov 6. doi: 10.1001/jamainternmed.2017.5512 [Epub ahead of print]