Aspirin is often prescribed to people who have experienced a heart attack or stroke, but a new study finds it may also be beneficial for cancer patients.

Researchers at the University of Cambridge recently discovered how aspirin may help prevent the spread of certain types of cancer. They focused on metastatic disease because when cancer has first spread, it’s more vulnerable to immune attack because it’s outside of the immunosuppressive environment in the tumor. That’s where aspirin comes in.

Aspirin works by reducing the production of thromboxane A2, or TXA2, which helps with blood clotting but can also cause heart attacks and strokes. The team’s research showed that TXA2 also suppresses T cells because when the cells are exposed to TXA2, it activates a protein called ARHGEF1.

According to the study, published in the journal Nature, T cell-specific deletion of ARHGEF1 in mice with melanoma increased T cell activation at the metastatic site, helping reject cancer’s spread to the lungs and liver.

This finding on the potential benefits of aspirin supports other research, which has shown that patients with certain types of cancer – including breast and colorectal - who take daily low-dose aspirin have a lower rate of metastasis. There is hope, then, that this may help early-stage cancer patients with a high risk of their cancer spreading.

Rahul Roychoudhuri, lead researcher and professor in the Department of Pathology at the University of Cambridge, says, “Despite advances in cancer treatment, many patients with early stage cancers receive treatments, such as surgical removal of the tumor, which have the potential to be curative, but later relapse due to the eventual growth of micrometastases – cancer cells that have seeded other parts of the body but remain in a latent state.

“Most immunotherapies are developed to treat patients with established metastatic cancer, but when cancer first spreads there’s a unique therapeutic window of opportunity when cancer cells are particularly vulnerable to immune attack. We hope that therapies that target this window of vulnerability will have tremendous scope in preventing recurrence in patients with early cancer at risk of recurrence.”

The team says they hope their research supports clinical trials on metastasis. They also say if that aspirin is proven to be effective, its effects can be widespread, as it’s more accessible globally than certain other immunotherapies.

You can read the whole study here.