Aspirin May Boost Immunity Against Cancer Cells

A new study reveals previously unknown mechanisms that explain how long-term daily use of aspirin can help to prevent colorectal cancer.

Previous research has suggested that the use of aspirin, a common nonsteroidal anti-inflammatory drug (NSAID), can prevent the development and progression of colorectal cancer, the second most common cause of cancer deaths in the United States.

However, the mechanisms behind aspirin's protective effects have been poorly understood.

The new study, published in the journal CANCER, suggests that the drug may boost certain aspects of the body's immune response against cancer cells.

To test the effects of aspirin, researchers in Italy obtained tissue samples from 238 patients who underwent surgery for colorectal cancer, 12% of whom were aspirin users.

Exposing colorectal cancer cells to aspirin in the lab increased the expression of a protein called CD80 on certain immune cells. This improved the cells' capacity to alert other immune cells of the presence of tumor-associated proteins.

In patients with rectal cancer, aspirin users had higher CD80 expression in healthy rectal tissue, supporting the findings in the cells.

"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 M.D., Ph.D., of the University of Padova.

Scarpa explains that when aspirin is administered orally, its concentration in the rectum can be much lower than in the rest of the colon. Therefore, it is crucial to guarantee that aspirin reaches the colorectal tract in adequate doses to be effective.

Preventing colorectal cancer

Besides its protective effects against colorectal cancer and polyps, daily aspirin can also reduce the risk of heart attack, clot-related strokes, and other blood flow problems in patients who have cardiovascular disease.

However, aspirin may not be a safe choice for pregnant individuals and people with conditions like uncontrolled high blood pressure, bleeding disorders, asthma, stomach ulcers, liver and kidney disease.

In 2022, the U.S. Preventive Services Task Force recommended against taking low-dose aspirin for prevention of a first cardiovascular event in people 60 years and older due to bleeding risks.

The risk of colorectal cancer increases with age and is higher in people with a family history of the disease. If you are 45 years and older, consider getting screened. You can also lower the risk by making healthy lifestyle choices:

• Maintain a healthy weight.
• Increasing the amount and intensity of your physical activity.
• Eat a diet rich in vegetables, fruits, and whole grains and low in red and processed meats.
• Don't consume alcohol, and quit smoking.

Daily aspirin may prevent the development of colorectal cancer and slow its progression, but it should not replace cancer treatment prescribed by a healthcare provider.