The study of 4,164 nurses was published online for the Journal of Clinical Oncology. It's the first study to find that regular aspirin users had a lower risk of dying from breast cancer, the newspaper reports.
The new study adds to a report in August that showed aspirin helped patients suffering from colon cancer.
Breast cancer study author Michelle Holmes of Harvard Medical School and Brigham and Women's Hospital told the newspaper that neither study definitively proves that aspirin helps fight off cancer. These conclusions just come from doctors observing which of their patients contracted cancer and which took aspirin.
"If a woman who had breast cancer is already taking aspirin, she might take comfort in knowing that perhaps she is also helping to keep her breast cancer from coming back," Holmes told the newspaper.
Some cancer patients are even told to avoid taking aspirin because it can act like a blood thinner. Patients who undergo radiation and chemotherapy treatments already experience a lower blood cell count.
Holmes told the newspaper no one should take aspirin as a replacement for conventional cancer treatment. The nurses in the new study had all undergone a complete course of treatment. The new study didn't measure how much aspirin the nurses took.