The benefits of aspirin make a low dose worthwhile for many patients.
Colorectal cancer (CRC) is the third most commonly diagnosed cancer among both men and women. It is also a leading cause of cancer death.
A low dose of aspirin each day is known to reduce the risk of heart attacks, stroke and cancer. However, among those who are susceptible, it can lead to bleeding in the stomach and intestines and strokes caused by bleeding in the brain.
The Mayo Clinic describe how aspirin can reduce the risk of cardiovascular disease (CVD) by preventing the blood from clotting.
Blood contains platelets, or clotting cells, which help to stop bleeding by accumulating at the site of a wound and forming a plug that seals the opening.
In the case of atherosclerosis, blood vessels are already narrowed, increasing the risk of clotting in the artery. A clot in the artery can stop blood from flowing to the heart, causing a heart attack.
Aspirin works by stopping the platelets from accumulating.
Weighing up the benefits and risks
The US Preventive Services Task Force (USPSTF) invited researchers to look at the combined benefits and harms of taking aspirin in three systematic evidence reviews and a modeling paper, before making recommendations based on these findings.
The three reviews confirm that aspirin can help both men and women to prevent first-time myocardial infarction and ischemic stroke. One study presents new evidence that aspirin can help reduce the risk of CRC.
The findings also reaffirm the risk of aspirin leading to major gastrointestinal bleeding and hemorrhagic stroke, posing a challenge for doctors who need to decide whether or not to prescribe regular aspirin for their patients.
The USPSTF commissioned the simulation modeling paper to assess the overall benefit of aspirin, depending on age, gender and risk for CVD.
Results from the model indicate that, for most people, a lifetime use of aspirin, starting between the ages of 50-69 years, can improve overall quality of life or decrease illness, as long as they do not have a risk of bleeding.
- Over 26 million Americans live with heart disease
- CVD, including heart disease and stroke, is responsible for 30% of deaths in the US
- In 2014, there were 137,000 new cases of CRC in the US, and it caused 50,000 deaths.
For patients aged 50-59 years with a 10% or higher 10-year risk of CVD, the USPSTF propose a low dose of aspirin to help prevent CVD and CRC. Patients should not be at high risk of bleeding, they should have a life expectancy of 10 years or more, and they should also be willing to take the dose for at least 10 years.
From 60-69 years, aspirin can reduce the risk of CVD in people with a 10% or higher chance of developing CVD within the next 10 years. Again, there should be no risk of bleeding, life expectancy should be 10 years or more, and the patient should be willing to take aspirin for at least 10 years. The decision should be agreed between the physician and the patient.
The USPSTF say that more research is necessary to assess whether taking aspirin is beneficial for people who are under 50 years or over 70 years.
In older patients without a risk of CVD, the risks associated with aspirin are considered too great to make its use worthwhile, and for those under 50 years, there is insufficient evidence on which to base a recommendation.
The USPSTF call on doctors to take patients' preferences into account and to encourage patient engagement when making these and other decisions.
The recommendations update those made by the USPSTF in 2009 about using aspirin to reduce the risk of CVD, as well as recommendations made in 2007 regarding the use of aspirin and non-steroidal anti-inflammatories (NSAID) to prevent CRC.The USPSTF note:
"[The] recommendation is based on the combined benefit of CVD and CRC reduction, and only at 10-year CVD risk levels of 10% or greater is there certainty that the benefits exceed the harms of low-dose aspirin use."
The Mayo Clinic urge patients not to begin taking aspirin alone, but to consult a doctor first, because of the risks.
Medical News Today recently reported on research stating that a low dose of aspirin can help prevent colorectal cancer.