Aspirin and Cancer Risk

The simple versionExplain▾

Aspirin is a common medicine used for pain, fever, and to thin the blood. You may have heard that it might also help prevent cancer.

There is some truth here. Research suggests that long-term, regular aspirin use may lower the risk of colorectal cancer in some people. But aspirin also carries risks, mainly bleeding.

Aspirin is not a general cancer-prevention pill, and it is not right for everyone. This is a decision to make with a doctor.

What the evidence showsExplain▾

Most of the promising evidence is about colorectal cancer, which starts in the colon or rectum. Several studies have found that people who take aspirin regularly over many years have a lower risk of this cancer.

For most other cancers, aspirin has not been shown to help. So the possible benefit is fairly specific, not broad.

How aspirin might helpExplain▾

Researchers are still studying exactly how aspirin may lower colorectal cancer risk. Two ideas stand out:

• Reducing inflammation. Aspirin lowers inflammation in the body, and ongoing inflammation can contribute to some cancers.
• Affecting cell pathways. Aspirin acts on certain pathways in cells that may play a role in how some cancers develop.

These effects may help prevent some colorectal cancers, but the full picture is not settled.

The bleeding riskExplain▾

Aspirin's benefits come with a real downside. Aspirin thins the blood, which can cause bleeding. The main concern is bleeding in the stomach and intestines. More rarely, aspirin can raise the risk of bleeding in the brain.

This risk is not the same for everyone. It tends to rise:

• With older age
• With certain health conditions
• With other medicines that also affect bleeding

Because aspirin is taken by people who do not have cancer, this bleeding risk has to be weighed carefully against the possible benefit.

Why the advice has changedExplain▾

Guidance about taking aspirin to prevent disease has shifted over the years. Earlier advice was more open to daily aspirin for many adults. As newer studies looked more closely at bleeding, especially in older adults, expert advice became more cautious.

This is a good reason to rely on a current conversation with your doctor rather than older advice you may remember. What was suggested years ago may not match today's guidance for your situation.

Making the decisionExplain▾

Whether daily aspirin makes sense for you depends on your personal picture. A doctor will weigh things like:

• Your age and overall health
• Your personal colorectal cancer risk
• Your bleeding risk
• Whether you already take aspirin for another reason, such as heart health

For some people, the possible benefit may outweigh the risk. For others, the bleeding risk is too high. There is no one-size-fits-all answer.

Aspirin is not a substitute for screeningExplain▾

Even if aspirin turns out to help you, it does not replace colorectal cancer screening. Screening tests, like colonoscopy and stool-based tests, remain a key way to find and prevent colorectal cancer by catching problems early.

Screening is recommended for most adults in the usual age range, whether or not they take aspirin. If you are curious about aspirin, bring it up with your care team, who can look at your full situation and help you decide.

A few things to keep in mindExplain▾

If you and your doctor decide aspirin is worth trying, or if you already take it, a few points help:

• Do not stop or start on your own. Some people take aspirin for heart reasons. Changing it without advice can cause problems.
• Watch for signs of bleeding. These can include black or bloody stools, vomiting blood, or unusual bruising. Report them to your doctor.
• Mention all your medicines. Some medicines raise bleeding risk when combined with aspirin.
• Revisit the decision over time. Your risk balance can change as you age or your health changes.

The bigger picture is that aspirin is one small, specific tool. It is not a cure-all, and it is not for everyone.

For most people, the strongest steps to lower cancer risk are not smoking, staying active, eating well, limiting alcohol, and keeping up with recommended screening. Aspirin may add a modest benefit for certain people at higher colorectal cancer risk, but only when a doctor has weighed it against the bleeding risk for that person.