Finding the best dose of aspirin to prevent Lynch Syndrome cancers
Lynch syndrome is an inherited genetic condition that significantly increases a person's lifetime risk of developing bowel cancer and certain other cancers. Past research showed that taking a high dose of aspirin every day can cut this cancer risk roughly in half. However, taking high doses of aspirin for a long time can cause unpleasant side effects, such as indigestion, stomach ulcers, or internal bleeding. This trial, known as CaPP3, aims to find the best balance. Doctors want to see if smaller daily doses (100 mg or 300 mg) work just as well as the traditional high dose (600 mg). Adults with a confirmed diagnosis of Lynch syndrome can take part. Everyone receives coated aspirin tablets to take daily. The ultimate goal is to find the safest, most effective dose to protect people with Lynch syndrome.
At a glance
What is this study about?
Lynch syndrome is a condition passed down through families. People with Lynch syndrome carry an alteration in genes that usually fix mistakes when DNA copies itself. Because these repair genes do not work properly, damaged cells are more likely to grow out of control, greatly increasing the risk of bowel, womb, and other cancers.
In earlier research, scientists discovered that taking aspirin every day helps people with Lynch syndrome by dramatically lowering their chances of getting bowel cancer. But that earlier study used a daily dose of 600 mg, which is quite large. Over time, high doses of aspirin can irritate the stomach lining and raise the chance of bleeding problems.
The CaPP3 trial was designed to solve this problem. Researchers are comparing three different daily doses of aspirin: 100 mg, 300 mg, and 600 mg. The tablets have a special coating designed to dissolve in the gut rather than the stomach, helping reduce irritation. By testing these three doses, doctors hope to discover if a lower, safer dose gives the exact same cancer-fighting benefits.
Key takeaways
- Tests three daily aspirin doses (100 mg, 300 mg, and 600 mg) to find the best balance of safety and cancer prevention.
- Aimed at adults aged 18 and older with a confirmed genetic diagnosis of Lynch syndrome.
- Tablets are specially coated to be gentler on the digestive tract.
- Aspirin treatment lasts at least two years alongside routine NHS cancer screenings.
- Taking part is voluntary, and you are free to stop at any time.
Who may be eligible?
This study is open to adults aged 18 and older who have had a genetic test confirming they have Lynch syndrome (specifically an alteration in genes such as MLH1, MSH2, MSH6, or PMS2). You must be able to swallow tablets and feel comfortable agreeing to the study rules.
You cannot take part if you have a known allergy to aspirin, aspirin-triggered asthma, or a history of stomach ulcers in the last three months. It is also not suitable for people with serious kidney disease, liver problems, bleeding disorders, or those who take prescription blood thinners.
Additionally, you should not join if you regularly take anti-inflammatory painkillers (like ibuprofen) more than three times a week, unless these can be safely stopped. Women who are pregnant, breastfeeding, or planning to become pregnant within the next two years are also unable to take part for safety reasons.
Could this study suit you?
Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.
- I am at least 18 years old.
- I have had a genetic test confirming I have Lynch syndrome.
- I am able and willing to swallow tablets every day.
- I do not have a history of bleeding disorders or stomach ulcers in the last three months.
- I am not allergic to aspirin and do not have aspirin-sensitive asthma.
- I am not pregnant, breastfeeding, or planning a pregnancy in the next two years.
What does participation involve?
If you take part, you will be placed into one of three groups by a computer. You will take either a 100 mg, 300 mg, or 600 mg dose of coated aspirin once every day. Neither you nor your trial doctor will choose or know your dose, which helps keep the results fair and unbiased.
You will take the tablets daily for at least two years. During this period, you will have regular check-ups with the research team to monitor your health, discuss any symptoms, and check your blood pressure. You will still attend all your standard NHS cancer checks, including routine colonoscopies. The study team will stay in touch with you over several years to monitor your long-term health.
Potential risks and benefits
Locations (1)
- Institute of Human GeneticsUnverifiedNewcastle Upon Tyne, England
Common questions
What is Lynch syndrome?
Lynch syndrome is an inherited genetic condition that makes a person more likely to develop certain cancers, especially cancer of the bowel and womb.
Why does aspirin help prevent cancer?
Aspirin reduces inflammation and seems to help the body identify and clear away faulty cells before they can turn into cancerous tumours.
Can I choose which dose of aspirin I receive?
No. A computer assigns you to the 100 mg, 300 mg, or 600 mg group at random so researchers can compare the doses fairly.
Will taking aspirin replace my routine colonoscopy screenings?
No. Aspirin provides an extra layer of protection, but regular bowel checks remain essential for detecting and removing polyps early.
What happens if I experience stomach ache or heartburn?
You should tell your study team straight away. They can evaluate your symptoms, offer medicine to protect your stomach, or stop the study pills if needed.
How to find out more
John Burn
Always speak to your GP or specialist before deciding to take part in a study.
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