Injectable blood thinners (anticoagulants) in patients with cancer
Research evidence suggests that blood thinners may improve the survival of patients with cancer, by preventing life-threatening blood clots and might also have a direct anticancer effect. However, blood thinners can also increase the risk of bleeding, which can be serious and reduce survival. It is therefore important to understand the pros and cons of treatment to allow patients and their doctors to be aware of the balance of risks and benefits.
We searched the scientific literature for studies of anticoagulants in people with cancer. The evidence is current to 14 August 2017. We included 18 eligible trials.
We selected 18 trials including 9575 participants with cancer. Most trials included participants with various types of cancer, especially small cell lung cancer, non-small cell lung cancer, and pancreatic cancer. All studies were conducted in the outpatient setting. The results suggest that the effect of injectable blood thinners on survival is uncertain, but if anything of small size. Also the results suggest that injectable blood thinners reduce the risk of blood clots by about half and possibly increase the risk of major bleeding and minor bleeding by 4 more per 1000 and 17 more per 1000, respectively. The effect on quality of life is uncertain.
Certainty of evidence
We judged the certainty of evidence to be high for symptomatic VTE and minor bleeding, and moderate for mortality, major bleeding and quality of life.
Editorial note: This is a living systematic review. Living systematic reviews offer a new approach to review updating in which the review is continually updated, incorporating relevant new evidence, as it becomes available. Please refer to the Cochrane Database of Systematic Reviews for the current status of this review.