An aspirin a day ‘weaponises’ immune system to hunt and destroy bowel cancer cells

AN ASPIRIN a day can ‘weaponise’ parts of the body’s immune system to help it destroy bowel cancer cells.

Previous research has shown that long-term aspirin use could help slash the risk of bowel cancer, stalling its development and progression, but scientists weren’t sure why.

Now a study published to the journal Cancer found that the common painkiller can have a protective effect against cancer by boosting certain parts of the body’s immune response against cancer cells.

Aspirin, also known as acetylsalicylic acid, belongs to a group of medicines called non-steroidal anti-inflammatory drugs (NSAIDs).

You can take it for pain relief if you’re over the age of 16.

People at risk of heart attacks and strokes may also be prescribed a low, daily dose of aspirin, as the drug can make your blood less ‘sticky’ and prone to clotting.

You should only take aspirin daily if you’ve been told to by a doctor.

While previous studies have warned that frequent use of the painkiller could cause internal bleeding in people over 60, taking aspirin has been linked to a lower risk of developing stomach, oesophageal, bowel and mouth cancer.

“The effect of aspirin on the chemoprevention of colorectal cancer is not only mediated by this single mechanism, but instead by several interrelated mechanisms, currently mostly unknown,” scientists from the University Hospital of Padova wrote.

The Italian researchers behind the recent study on aspirin and bowel cancer risk obtained tissue samples from 238 patients who underwent surgery at the hospital for the disease between 2015 and 2019.

Thirty-one (12 per cent) of these patients were “aspirin users”, meaning they’d started taking a low 100mg dose of aspirin at least a year before their bowel cancer diagnosis, to lower the risk of heart attacks or strokes.

Samples of daily aspirin takers showed that their bowel cancer had spread less into their lymph nodes.

There was also a higher concentration of immune cells in their tumours, compared to samples from patients who didn’t take aspirin.

Researchers from the University Hospital of Padova also analysed how bowel cancer cells responded to aspirin in the lab.

They found that exposing the cells to aspirin caused increased expression of a protein called CD80 on certain immune cells, which enhanced the capacity of the cells to alert other immune cells of the presence of proteins associated with tumours.

Researchers found similar results in patients with rectal cancer, supporting their findings.

Aspirin users with rectal cancer had higher CD80 expression in healthy rectal tissue, suggesting that aspirin can boost the immune system’s cancer surveillance abilities.

“Our study shows a complementary mechanism of cancer prevention or therapy with aspirin besides its classical drug mechanism involving inhibition of inflammation,” said principal investigator Marco Scarpa MD, PhD, of the University of Padova.

“Aspirin is absorbed in the colon by passive diffusion to a significant degree,” he explained.

But he noted that how much aspirin is absorbed “depends on concentration along the bowel”.

“In the rectum, the concentration of orally administered aspirin can be much lower than in the rest of the colon,” Dr Scarpa added.

“Thus, if we want to take advantage of its effects against colorectal cancer, we should think of how to guarantee that aspirin reaches the colorectal tract in adequate doses to be effective.” 

Research has also shown that frequent aspirin use could cut your risk of developing ovarian cancer.

But another study published last year suggested that regularly popping an aspirin if you haven’t been told to by a doctor can also increase your risk of developing anaemia – especially if you’re 65 and older.