Heparin does not appear to impact 1- and 2-year mortality in people with cancer, according to a Cochrane review of 18 trials involving nearly 9,600 individuals. Studies included patients mainly with small cell lung cancer, non-small cell lung cancer, and pancreatic cancer. Among the findings:

• The impact on blood thinners is uncertain, or small at best.
• Injectable blood thinners reduce the risk of blood clots by about half.
• They appear to increase the risk of major bleeding by 4 more per 1,000, and minor bleeding by 17 more per 1,000.
• Quality of life impact is not certain.

The decision to start heparin therapy should balance the benefits and downsides, and should include patient values/preferences, the reviewers noted.