Prostate biopsy results: PIN and ASAP

PIN and ASAP are changes in the cells in the prostate, which can only be seen under a microscope. PIN stands for prostatic intraepithelial neoplasia. ASAP stands for atypical small acinar proliferation.

What is PIN?

PIN is not prostate cancer. It involves changes to the cells in the prostate that can only be seen under a microscope. The cells may grow in a different way to normal prostate cells.

We don't know what causes PIN, but we do know that the chance of finding it increases as you get older. 

If you've been diagnosed with PIN, it's probably high-grade PIN. There is also low-grade PIN, but there's very little evidence that this can cause problems in a man's lifetime. You can check with your doctor if you're not sure. When we say PIN, we mean high-grade PIN.

Although PIN is not prostate cancer, many men with prostate cancer do have some PIN as well. It is also possible to find PIN in a biopsy sample without finding prostate cancer.

What is ASAP?

ASAP stands for atypical small acinar proliferation. ASAP isn’t a medical condition but it is a term used to describe changes to prostate cells seen under the microscope, when it isn’t clear whether the cells are cancer. For example, there may not be enough changed cells for the doctor to say whether they are cancer. If you have ASAP, your doctor may recommend more tests so that any further cell changes are found early.

It's possible to have both ASAP and PIN in your prostate.

Am I more likely to get prostate cancer if I have PIN or ASAP?

If PIN or ASAP is found in your first biopsy sample, your doctor may suggest that you have further biopsies later on. The second biopsy could contain prostate cancer that needs treatment.

• Around 8 in 100 men with PIN will be diagnosed with prostate cancer that needs treatment after a second biopsy.
• Around 6 in 100 men who have ASAP will be diagnosed with prostate cancer that needs treatment after a second biopsy.

If you've been diagnosed with PIN or ASAP and are worried about prostate cancer, speak to your doctor or nurse. Read more about your risk of getting prostate cancer. Or you could speak to one of our Specialist Nurses.

Researchers are looking at whether certain diets or medicines can help to prevent prostate cancer in men with PIN. But we need more evidence for these. Remember, many men with PIN or ASAP will not get prostate cancer.

What are the symptoms of PIN and ASAP?

PIN doesn’t cause any symptoms. But it’s usually diagnosed when a man has tests or surgery for another prostate problem that does have symptoms. For example, if you have an enlarged prostate as well as PIN, you might have problems urinating (weeing). These are caused by the enlarged prostate, not the PIN.

If you are diagnosed with ASAP, the changed cells may or may not be cancer. If they are cancer, they may cause symptoms in the future.

If you do have any symptoms such as problems urinating, speak to your doctor. They can do more tests to find out what’s causing them, and suggest treatments that may help.

How are PIN and ASAP found?

PIN and ASAP can only be found by looking at prostate tissue under a microscope. This might happen if:

• you have a biopsy to check for prostate cancer.
• you have surgery, called a transurethral resection of the prostate (TURP) or holmium laser enucleation of the prostate (HoLEP) to treat an enlarged prostate.

A doctor who specialises in checking cells under a microscope (a pathologist) will look at the samples. They will send your doctor a report, called a pathology report, with the results. The results will show:

• whether they found any PIN, ASAP or cancer in your prostate
• how many samples were affected
• how much PIN, ASAP or cancer was in each sample.

Ask your doctor or nurse to explain your test results, or you can speak to our Specialist Nurses.

How common are PIN and ASAP?

We don’t know how many men in the UK have PIN or ASAP. But for men who have had their prostate tissue looked at under a microscope (after a biopsy, for example):

• around 5 in 100 men (five per cent) have PIN
• around 5 in 100 men (five per cent) have ASAP.

Black men are more likely to get PIN than white men of the same age. Some research also suggests Black men may get a larger amount of PIN at an earlier age than white men. But we don’t fully understand the reasons for this. There hasn’t been much research to look at how likely it is for mixed-race men to get PIN or ASAP.

We do know that Black men are more likely to get prostate cancer than other men of the same age in the UK. In fact, one in four Black men will be diagnosed with prostate cancer. But we still don’t know the reasons why. Read more in our leaflet, Prostate cancer and other prostate problems: Information for Black men.

There hasn’t been any research to look at how likely it is for Asian or mixed-race men to get PIN or ASAP.

Will I need treatment for PIN and ASAP?

You won't need any treatment for PIN or ASAP, but you might need regular check-ups every few months. This is to check for any cancer cells that may have been missed by the first biopsy.

You may have:

• regular PSA blood tests
• MRI scan
• another biopsy

The tests you have will depend on your own situation. Talk to your doctor or nurse if you have any questions. You can also speak to our Specialist Nurses.

If you are diagnosed with cancer, it is more likely to be an early stage because you'll have had these regular check-ups. This means it can be carefully monitored or treated if necessary.

If you do go on to develop prostate cancer, you won't have any more check-ups for PIN or ASAP.

Where can I get support?

There’s still a lot we don’t know about PIN and ASAP. We know this can be frustrating and you might be anxious about getting prostate cancer.

Sometimes, when men are diagnosed with PIN or ASAP they find it helpful to find out more about prostate cancer. Most prostate cancers grow slowly or don’t grow at all. They may never cause any problems or shorten a man’s life. These cancers can often be monitored with regular check-ups instead. But some prostate cancers do grow quickly and are more likely to cause problems. They will need treatment to stop them spreading. Read more about the different types of prostate cancer.

If you are worried about your biopsy results, our Specialist Nurses are here to talk through your concerns and help answer any questions you might have.

Questions to ask your doctor or nurse

• Have I got high-grade PIN or ASAP?
• How much high-grade PIN or ASAP do I have?
• Do I need further tests to find out more?
• What is my risk of getting prostate cancer?
• How often will I need to have check-ups?
• What will my check-ups involve?
• Will I need to have another biopsy?
• What kind of biopsy will I need?
• Will I need any other tests?

List of references and reviewers

Updated August 2025 | Due for review August 2028