Aspirin can bolster the body’s immune responses against the spread of cancer from its primary site to other organs, scientists said on Wednesday, reporting the discovery of a previously unknown pathway shown to work against multiple cancers in lab mice.
A research team led by cancer immunologist Rahul Roychoudhuri at the University of Cambridge has found a novel immunosuppressive pathway targeted by aspirin to enhance immune responses against metastasis, which causes 90 per cent of cancer deaths worldwide.
In their study, mice with breast, colon and skin cancer treated with aspirin showed lower levels of metastasis — the spread of cancer to other organs such as the lungs or the liver — than mice with the cancers that did not receive aspirin.
The findings, published in the journal Nature on Wednesday, provide “mechanistic insights” into the anti-metastatic activity of aspirin and could pave the way for novel treatments that mimic this effect of aspirin without its potential risks.
“While previous studies and trials had shown aspirin’s potential benefits against metastasis, our study is the first to identify the specific immunological pathway involved,” Roychoudhuri told The Telegraph.
Roychoudhuri and his colleagues have shown that a key anti-platelet action of aspirin, which lowers the production of a molecule called thromboxane A2, enhances the capacity of the immune system’s cells to fight metastatic
cancer cells.
“This elegant study provides the missing piece of the jigsaw puzzle,” Mangesh Thorat, a consultant breast cancer surgeon at the Homerton University Hospital, London, who was not associated with the study, said in a statement released by the UK Science
Media Centre.
Clinical trials to evaluate aspirin as an adjunct treatment to prevent metastasis are under way.
Among the clinical trials is one named ADD-ASPIRIN that has recruited over 10,000 patients with early-stage breast, colorectal, gastro-oesophageal and prostate cancers across India, Ireland and the UK, with the Tata Memorial Centre hospital in Mumbai as the India participating centre.
“This is a double-blind randomised controlled trial where neither patients nor doctors know who is getting aspirin and who is getting placebo pills,” said Sudeep Gupta, a medical oncologist at the TMC and lead investigator who helped recruit breast cancer patients for the ADD-ASPIRIN trial.
The results from these trials are expected to emerge within the next two to five years, said Roychoudhuri, who was born and raised in the UK. His father, Dhirendra Nath Roychoudhuri, an obstetric-gynaecology surgeon, had grown up in Harinarayanpur near Calcutta and emigrated to practise in the UK.
Roychoudhuri and other doctors caution that while aspirin is attractive because of its low cost and easy access, it is not a risk-free medicine. Long-term aspirin use is associated with gastrointestinal toxicity, including peptic ulceration and gastrointestinal bleeding.
“Our research suggests aspirin could potentially be most beneficial for patients with early-stage cancers who’ve been treated with curative intent but might have undetected micrometastases,” Roychoudhuri said. “However, further clinical validation is needed before recommendations (for aspirin) can be made.”
Alan Melcher, a cancer immunologist who was not associated with the study, said its findings were unlikely to directly change how people might use aspirin. “But this new research may help design better, more targeted drugs that interfere with the mechanism discovered here to do the good things that aspirin does without its harmful side effects,” Melcher said.