How Aspirin May Reduce Cancer Metastasis

A study led by researchers at the University of Cambridge has uncovered the mechanism behind aspirin's potential to reduce cancer metastasis. Published in Nature, the research explains how aspirin stimulates the immune system to prevent the spread of certain cancers, including breast, bowel, and prostate cancers.

The scientists discovered that aspirin works by decreasing thromboxane A2 (TXA2), a clotting factor produced by platelets. This reduction in TXA2 releases T cells from suppression, allowing them to recognize and kill metastatic cancer cells more effectively. The research team used a mouse model of melanoma to demonstrate that aspirin reduced the frequency of metastases compared to control mice.

Professor Rahul Roychoudhuri, who led the study, emphasized the importance of targeting the "window of vulnerability" when cancer first spreads. “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 discovery was serendipitous, as the team was initially investigating the process of metastasis and the immune system's response to it. According to first author Jie Yang, “It was a Eureka moment when we found TXA2 was the molecular signal that activates this suppressive effect on T cells. Before this, we had not been aware of the implication of our findings in understanding the anti-metastatic activity of aspirin. It was an entirely unexpected finding which sent us down quite a different path of enquiry than we had anticipated.”

While the findings are promising, the researchers caution that aspirin can have serious side effects in some people. Ongoing clinical trials, such as the Add-Aspirin trial led by Professor Ruth Langley, aim to determine how to use aspirin safely and effectively to prevent cancer spread.