The role of aspirin in cancer therapy remains a topic of ongoing debate. In some cancers (such as colorectal cancer, particularly in patients with Lynch syndrome) its benefit as an adjuvant treatment is both statistically and clinically established.
For other cancer types, however, the evidence is limited to retrospective studies. Now, a new study published in May 2025 in Nature offers insight into an additional mechanism by which aspirin may help combat cancer.
Could this also be relevant for prostate cancer? Theoretically, yes, because the mechanism described appears to be common across multiple cancer types, including prostate cancer.
The study reveals that aspirin, a common drug, can help stop cancer from spreading by boosting the immune system. This research by Yang et al. offers a simple way to fight metastasis—the process where cancer moves to new parts of the body, causing 90% of cancer deaths.

The study found that aspirin reduces cancer spread in mice with cancers like melanoma and lung cancer. In experiments, mice treated with aspirin had fewer tumors in their lungs and liver compared to untreated mice. This happened because aspirin helps immune cells, called T cells, attack cancer cells trying to spread. The research also notes that human studies show aspirin users have a lower risk of metastasis (64% less likely) and fewer cancer deaths in early-stage cases (49% less likely), especially in cancers like colorectal cancer with strong immune markers.

When cancer cells try to spread, T cells should stop them, but platelets release a molecule called TXA2 that weakens T cells, letting cancer escape. Aspirin blocks an enzyme (COX-1) in platelets, stopping TXA2 production. With less TXA2, T cells stay strong, multiply, and release proteins like IFNγ to kill cancer cells. In the study, mice without TXA2 (due to aspirin or genetic changes) had fewer metastases because their T cells worked better. It’s like aspirin removes a brake, letting T cells fight harder.

The findings suggest aspirin could help prevent cancer spread in people, especially those with early-stage cancer at risk of metastasis. The study showed aspirin works best when T cells are active, which might explain why it helps some patients more. The research also hints that aspirin’s effects might be stronger in cancers with active immune responses, like colorectal cancer.
Aspirin’s low cost makes it a promising tool, but more studies are needed to confirm how it works in different cancers and people. The researchers suggest developing new drugs that target TXA2 more precisely to avoid aspirin’s side effects. For now, this study offers hope that a familiar drug could keep cancer from spreading by powering up the immune system.

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