Updated 13 April 2017

Aspirin lowers risk of cancer

New research implies that aspirin use may prevent a significant number of colorectal cancers above and beyond those that would be prevented by screening.


People who take aspirin regularly have a significantly lower risk of cancer, particularly involving the colon and gastrointestinal tract, according to US research.

Protective benefit

The findings in the Journal of the American Medical Association (JAMA) Oncology suggest that aspirin use should complement – not replace – already established preventive cancer screening measures such as colonoscopies.

"We now can recommend that many individuals consider taking aspirin to reduce their risk of colorectal cancer particularly those with other reasons for regular use, such as heart disease prevention," said senior author Andrew Chan of the Massachusetts General Hospital.

Read: Daily aspirin can drastically cut cancer rates

"Our findings imply that aspirin use would be expected to prevent a significant number of colorectal cancers above and beyond those that would be prevented by screening and may have even greater benefit in settings in which the resources to devote to cancer screening are lacking."

Previous research has shown that regular aspirin use can help prevent colorectal cancer.

However, the wider effect of aspirin on all cancers was less clear.

So the researchers looked at 32 years' worth of data from nearly 136,000 nurses and health professionals who answered health surveys.

Read: Daily aspirin may guard against ovarian cancer

People who took either a regular aspirin or a low-dose aspirin at least twice per week showed a three percent lower risk of any type of cancer than those who did not report regular aspirin use.

The protective benefit of aspirin "appeared after five years of continuous use at dosages ranging from 0.5 to 1.5 standard tablets a week or one low-dose tablet a day", said the study.

Observational studies

Aspirin use reduced the risk of colorectal cancer by 19 percent and the risk of any gastrointestinal cancer by 15 percent.

Regular aspirin use "could prevent close to 30,000 gastrointestinal tract tumours in the US each year", said the study.

Read: Aspirin may keep cancer at bay

The team also calculated that aspirin use could "prevent an additional 7,500 colorectal tumours among US adults over 50 who have endoscopic screening and 9,800 among the almost 30 million who are not screened".

However, when researchers looked specifically at common cancers such as breast, lung and prostate cancer, they found no risk reduction from aspirin use.

The research was based on observational studies, so it is not as strong as a randomised controlled trial.

Aspirin also carries certain risks, such as bleeding and stroke, and cannot be tolerated by everyone.

The US Preventive Services Task Force recommends aspirin to prevent colorectal cancer and cardiovascular disease among many US adults. 

Read more: 

What is cancer? 

Types of cancer 

Preventing cancer


Ask the Expert

Cancer expert

CANSA’s purpose is to lead the fight against cancer in South Africa. Its mission is to be the preferred non-profit organisation that enables research, educates the public and provides support to all people affected by cancer. Questions are answered by CANSA’s Head of Health Professor Michael Herbst. For more information, visit

Still have a question?

Get free advice from our panel of experts

The information provided does not constitute a diagnosis of your condition. You should consult a medical practitioner or other appropriate health care professional for a physical exmanication, diagnosis and formal advice. Health24 and the expert accept no responsibility or liability for any damage or personal harm you may suffer resulting from making use of this content.

* You must accept our condition

Forum Rules