A study of active surveillance, aspirin and vitamin D in men with prostate cancer (PROVENT)

Please note - this trial is no longer recruiting patients. We hope to add results when they are available.

Cancer type:

Prostate cancer





This study is for men having regular monitoring for prostate cancer contained within the prostate gland (localised prostate cancer).

More about this trial

Prostate cancer can grow so slowly that it never causes any symptoms. So, some men with localised prostate cancer have regular monitoring. This is called active surveillance. It means you don’t have treatment straight away. Your doctor keeps a close eye on you to check for any signs that the cancer is growing. If it does, then you and your doctor will decide which treatment is best for you.

Some newer research suggests that having aspirin and vitamin D3 can stop cancer from growing and changing. So researchers want to find out more. In this study, they want to see how useful these drugs are in men having active surveillance.

This is a feasibility study. This helps the study team to check the design before running a larger trial. The aims of this study are to find out:

  • how willing men are to take part
  • how well treatment works for prostate cancer that has a low risk of growing or spreading

Who can enter

The following bullet points list the entry conditions for this study. Talk to your doctor or the study team if you are unsure about any of these. They will be able to advise you. 

You might be able to join this study if all of the following apply. You

  • Have stage T1 or T2 prostate cancer that hasn’t spread outside the prostate
  • Have a PSA level Open a glossary item that is less than or equal to15
  • Have a Gleason score Open a glossary item of 6 or 7 
  • Are having or due to have regular monitoring (active surveillance) of your prostate cancer 
  • Have had an MRI scan of your prostate within a year of joining the study and the doctor took tissue samples (biopsies) of any lesions found 
  • Have satisfactory blood test results 
  • Are at least 16 years old

You cannot join this study if any of these apply. You

Cancer related

  • Have had treatment for prostate cancer including radiotherapy, hormone therapy, brachytherapy or surgery

Medical conditions

  • Have or have had bleeding anywhere in your stomach or bowels, peptic ulcer, severe indigestion or inflammatory bowel disease 
  • Have a bleeding condition called haemophilia or any other bleeding problem such as thrombocytopenia 
  • Have had kidney stones in the past
  • Have severe, long term kidney problems
  • Have high levels of calcium in your blood or a condition called hyperparathyroidism that isn’t well controlled with medication
  • Have any bowel condition such as a fistula that would make taking tissue samples via the rectum risky or difficult 
  • Have had any other cancer apart from non melanoma skin cancer Open a glossary item that has been successfully treated in the last 5 years
  • Have any other serious medical condition that would make repeat prostate biopsy risky such as significant bleeding problems
  • Have severe asthma
  • Have a genetic disorder called G6PD that affects red blood cells
  • Have an eye condition called macular degeneration


  • Are taking aspirin, non steroidal anti inflammatory drugs (NSAIDS) Open a glossary item or vitamin D3 or you have taken 6 months of aspirin or vitamin D3 within 2 years of joining this study
  • Are taking or have taken drugs such as finasteride or dutasteride
  • Are sensitive or allergic to aspirin or NSAIDS such as ibuprofen or naproxen
  • Can’t have aspirin or vitamin D3 for any reason or you are taking any medicine that might interact with these
  • Drink more alcohol than the recommended daily limit of 3 to 4 units per day

Trial design

This feasibility study is based in the UK. The researchers need 102 men to take part.

It is a randomised study. You are put into 1 of 6 groups. Neither you nor your doctor will be able to decide which group you are in. And neither of you will know which group you are in either. This is called a double blind study. You have 1 of the following:

  • the usual dose of aspirin (300mg) and vitamin D3
  • the usual dose of aspirin and dummy drug (placebo Open a glossary item) vitamin D3
  • low dose aspirin (100mg) and vitamin D3
  • low dose aspirin and dummy vitamin D3 
  • dummy aspirin and vitamin D3
  • dummy aspirin and dummy vitamin D3 

study diagram

Aspirin and dummy aspirin are tablets. You take aspirin or the dummy drug once a day, everyday.

Vitamin D3 and dummy vitamin D3 are an oily liquid. You have a few drops once a day, everyday. You can take them on their own, soaked in some bread or in a small amount of fruit juice.

You have treatment for up to a year and a half.

Hospital visits

You see a doctor and have some tests before you can take part. These include:

  • a test to check for a stomach infection called Helicobator pylori
  • a poo (stool) sample test
  • blood tests
  • a urine test 
  • an examination of your back passage (rectum Open a glossary item

You see the study team every 3 months for a check up. At each visit you have some blood tests. 

A year after you join the study: 

  • you have an MRI scan 
  • the doctors take a tissue sample (biopsy) of your prostate

Side effects

Aspirin is a commonly used drug with very few side effects. The most serious side effect of aspirin is a slightly increased risk of bleeding. 

Other possible side effects include:

  • tummy (abdominal) upset or pain 
  • feeling or being sick 
  • heartburn 
  • diarrhoea 
  • blood in the stool or black stools 

Very rarely, people have an allergic reaction to aspirin. And it can sometimes make asthma worse.

The study team recommend that while you are taking part in the study you do not take any extra aspirin or NSAIDS such as ibuprofen. 

Side effects from vitamin D3 are very rare. Possible side effects include:

  • high levels of calcium in the blood or urine
  • feeling sick
  • diarrhoea
  • tummy (abdominal) pain
  • skin rash

The study team will talk to you about all the possible risks before you agree to join.

Recruitment start:

Recruitment end:

How to join a clinical trial

Please note: In order to join a trial you will need to discuss it with your doctor, unless otherwise specified.

Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Chief Investigator

Mr Greg Shaw

Supported by

Barts and the London Charity
Experimental Cancer Medicine Centre (ECMC)
Queen Mary University of London

Freephone 0808 800 4040

Last review date

CRUK internal database number:


Please note - unless we state otherwise in the summary, you need to talk to your doctor about joining a trial.

Keith took part in a trial looking into hormone therapy

A picture of Keith

"Health wise I am feeling great. I am a big supporter of trials - it allows new treatments and drugs to be brought in.”

Last reviewed:

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