Aspirin, already known to reduce risk of getting cancer, may soon become part of the regimen for patients who already have cancer.

Researchers at University of Cardiff conducted a meta-analysis of 47 studies—two randomized trials and 42 observational studies—of people with cancers of the breast, bowel and prostate, some of whom took low-dose aspirin in addition to their regular cancer treatment.

Results: For those who had aspirin therapy added at some point to their cancer treatments, their cancers were less likely to spread and, over the five-year period studied, they were 20% less likely to die.

Aspirin has been around for more than 100 years and is one of the most researched medicines in the world. It’s easily available, cheap and relatively safe. But it’s not risk-free. For one thing, taking aspirin regularly increases the chance for internal bleeding, although the researchers did report that no serious or life-threatening bleeding was reported in the studies that they analyzed.

For someone who is being treated for cancer, the best advice is to discuss with your doctor whether it makes sense to add low-dose aspirin to your treatment plan. Given the strength of the potential benefit, it’s an essential conversation.

For more about how to take aspirin safely, read Bottom Line’s “The Aspirin Question.”