Tuesday, 7 November 2017

Warfarin prevents cancer - A new discovery or a scientific myth?

Recently an article published in JAMA pointed out towards possible benefits of warfarin in terms of preventing any type of cancer. (1) The study employed the Norwegian registry with over a million patients involved in the study. The authors concluded that warfarin decreases the incidence of cancer, with incidence risk ratio of 0.84, 95% CI 0.82-0.86. As good as the results and sample size sounds, the study itself was plagued by some serious limitations.

It's a well known fact that cancer is a multifactorial disease and it's incidence and prevalance is highly impacted by the environmental, socio-economics and lifestyle factors of the society. The authors have admitted their limitations that the data was lacking the most common lifestyle factors of patients which include smoking status, alcohol use, dietary habits, family history or BMI. The lack of the factors can significantly alter the results.

Therefore, making this conclusion that warfarin prevents cancer without stratifying the results based on other causations of cancer makes the conclusion invalid and false positive. Although it is know that warfarin has potential link with  inhibition of certain molecules that promote cancer formation. However, without a valid study design, such conclusion can not be made in population studies. The study has a major flaw and therefore a repeat study should be done with the above factors involved in order to correctly correlate warfarin with cancer prevention.