The aim of cancer screening
Screening means looking for early signs of a particular disease in healthy people who don’t have any symptoms. The aim of screening is to detect disease at an early stage before symptoms start. It is then easier to treat and more likely to be cured.
Currently, there is no test in existence that can reliably find cancers that would cause problems during a man’s lifetime. Today, we have the PSA test which helps doctors work out how likely a man is to have prostate cancer. However, this test is not specific enough to use as part of a national screening programme. There currently is no clear evidence that screening using PSA testing could save lives. There is also clear evidence that the PSA test can lead to tests and treatment for some men that cause harm as prostate cancer can grow very slowly and not lead to any symptoms. PSA testing can pick up some of these cancers and may lead to tests and treatment that the man doesn’t need. The treatment can cause problems such as incontinence or erectile dysfunction which negatively effect a man’s quality of life while the cancer itself was causing no issues.
Research studies into using the PSA test for prostate cancer screening have had conflicting results. So we don’t know whether screening would help to reduce deaths from prostate cancer.
By the age of 80, many men will have some cancer cells in their prostate, but only 1 in 25 of them will actually die from prostate cancer. On the other hand, some prostate cancers are faster growing and can spread to other parts of the body within a few years.
In order for a screening programme to be helpful in the same way that BreastCheck and other screening programmes are, a prostate cancer test would need to only pick up prostate cancers that are faster growing and likely to be a threat to a man’s health. At the moment, there is no test that can reliably do this.
The PSA test
Prostate-specific antigen, or PSA, is a protein produced by cells of the prostate gland. The PSA test measures the level of PSA in a man’s blood. For this test, a blood sample is sent to a laboratory for analysis. The results are usually reported as nanograms of PSA per milliliter (ng/mL) of blood.
PSA levels can be raised if a man has prostate cancer. But other medical conditions can also cause PSA levels to rise, such as an enlarged prostate that is not cancer called benign prostatic hyperplasia or BPH.
PSA can also be raised by prostate infection (prostatitis), exercise and sex. Some drugs used to treat a benign enlarged prostate can lower PSA.
Another problem is that all men have slightly different PSA levels. It is difficult to say what is normal, and what is high. This means that not all men with high PSA have prostate cancer. And not all men with prostate cancer have high PSA levels.
- Most healthy men have PSA levels under 4 nanograms per milliliter (ng/mL) of blood. The chance of having prostate cancer goes up as the PSA level goes up.
- When prostate cancer develops, the PSA level usually goes above 4. Still, a level below 4 does not guarantee that a man doesn’t have cancer – about 15% of men with a PSA below 4 will have prostate cancer on a biopsy.
- Men with a PSA level between 4 and 10 have about a 1 in 4 chance of having prostate cancer. If the PSA is more than 10, the chance of having prostate cancer is over 50%.
Generally speaking, the higher the PSA level, the more likely it is that there is a cancer in the prostate. But in early prostate cancer, PSA levels are usually relatively low. It is not possible to pick out a particular PSA reading and say “people above this level have cancer and those below don’t”. The PSA level also naturally tends to get higher as men get older.
Risks and benefits of PSA test
There are benefits of having a PSA test which include early detection of prostate cancer. The earlier cancer is detected, the better the chance of a cure.
There are also risks involved. These include:
- Worry about false-positive results caused by elevated PSA levels from something other than prostate cancer. A raised PSA result could be from something benign (non-cancerous)
- Invasive, stressful, expensive or time-consuming follow-up tests
- Stress or anxiety caused by knowing you have a slow-growing prostate cancer that doesn’t need treatment
- Deciding to have surgery, radiation or other treatments that cause side effects that are more harmful than untreated cancer
If you want a PSA test
Although there is no prostate screening programme, men aged over 45 can ask their GP for a PSA test.
If you ask to have the test your GP first explains all the possible benefits and risks. They give you written information to read. Your doctor or practice nurse can answer any questions that you have.
If you still want to have the test after considering the information, your GP or practice nurse will take a blood sample.
If you have the test you should not have
- A urinary tract infection (UTI)
- Ejaculated for 48 hours beforehand
- Exercised heavily in the previous 48 hours
- Had a prostate biopsy within the last 6 weeks
These things may raise your PSA level.
Your GP may also examine your prostate. They do this by gently putting a gloved finger into your back passage (bottom) and feeling your prostate gland. They call this digital rectal examination or DRE.
After a PSA test
You usually get your PSA test result within a couple of weeks.
If you have a normal PSA level, experts currently think that you don’t need another test for at least 2 years.
If your PSA level is slightly raised, you should have a repeat test about 6 weeks later to see if the PSA level is going up or is stable. There are guidelines for GPs about what to do in these circumstances.
If you have a raised PSA, your doctor will refer you to a specialist for further tests. These tests include an examination of your prostate gland and possibly a prostate biopsy.
PSA testing for men at higher risk of prostate cancer
Some men may start having regular PSA tests at an earlier age if they have an increased risk of developing prostate cancer such as having a direct family member (father or brother) with prostate cancer or if you are black-African or black-Caribbean. You can read more about risk factors for prostate cancer here.
Should I see a prostate cancer specialist?
Referrals from your GP
The symptoms of prostate cancer can be very similar to some other prostate problems, so it can be very difficult for GPs to decide who may have a suspected cancer and who may have something much more minor that will go away on its own.
Read about the symptoms of prostate cancer.
There are particular prostate symptoms that mean your GP should refer you to a specialist straight away. The National Cancer Control Programme (NCCP) has produced guidelines for GPs in Ireland. The guidelines help GPs decide which patients need to be seen urgently by a specialist called a urologist. A urologist is a doctor who specialises in treating disorders of the urinary tract, including the kidney, bladder and prostate.
Points to remember about referral guidelines
While reading these guidelines, it is important to remember that
- PSA testing of men who do not have symptoms or PSA screening is not national policy, a prostate assessment consists of a digital rectal examination (DRE) and a PSA test.
- PSA testing should only be carried out after full advice and provision of information
- More than 99 out of every 100 men diagnosed with prostate cancer are over 50
- About 75 out of every 100 men diagnosed with prostate cancer are over 70
- The cumulative risk of a man developing prostate cancer before the age of 50 is 1 in 485 and before the age of 70 is 1 in 13
- Difficulty passing urine is common in the general population and on its own, is not a reason for your GP to suspect prostate cancer
- The most common signs of prostate cancer are a raised PSA blood test and an abnormality found by your GP during an examination of your prostate (digital rectal examination)
- A normal PSA reading varies depending on your age
- Men with a first degree relative (mother, father, son or daughter) who have prostate or breast cancer are at a higher risk of developing prostate cancer themselves
PSA testing
PSA stands for prostate specific antigen. This is a substance made by normal and cancerous prostate cells and released into the bloodstream. The level of PSA in your blood may go up in prostate cancer because more PSA leaks into the bloodstream from the cancerous cells. PSA levels also go up as you get older and if you have a benign (non cancerous) enlarged prostate. So the PSA test is not a specific test for cancer.
There is a range of normal PSA readings for every age group.
| Age | PSA Reference Ranges (ng/ml) |
|---|---|
| 40-49 | 0-2.5 |
| 50-59 | 0-3.5 |
| 60-69 | 0-4.5 |
| 70-79 | 0-6.5 |
Corresponding reference ranges for men of African ethnicity are 0-2.0ng/ml (40-49yrs), 0-4.0ng/ml (50-59), 0-4.5ng/ml (60-69yrs) and 0-5.5ng/ml (70-79).
There is no national screening programme in place for prostate cancer in Ireland. This is because research studies have shown that routine PSA screening may reduce some deaths from prostate cancer. But screening can also lead to unnecessary tests or treatments that can cause unpleasant side effects and may reduce quality of life.
If you don’t have any symptoms of prostate cancer, are over 45 and want to have a PSA test, speak to your GP. Your GP will give you information about the benefits and possible harms of the test. You will be able to have the test if you choose to after you have considered the risks and benefits.
Men under the age of 45 who have a close family member with prostate cancer, and black-African and black-Caribbean men, have a higher risk of prostate cancer than the general population. They can talk to their GP, who can assess their individual risk of prostate cancer and offer PSA testing if appropriate.
Guidelines for urgent referral
According to the NCCP guidelines, you should ideally get an appointment within 4 weeks (an urgent referral) if you have certain symptoms. The symptoms are:
- Abnormalities in your prostate that your GP can feel during a rectal examination
- A PSA test that is considered high for your age
- A borderline PSA test, followed by a repeat test 6 weeks later that shows the level is rising
- A raised PSA reading, together with other symptoms that may be linked to prostate cancer
The symptoms that the guidelines suggest GPs should also consider are:
- Unexplained weight loss (especially if you are elderly)
- Low back pain or other bone pain
- Blood in the urine
- Problems getting an erection (when you have not had problems before)
The guidelines say that your GP should offer to do a rectal examination and a PSA test if you have these symptoms.
Talking to your GP
If you are worried that your GP is not taking your symptoms as seriously as you think they should, you could print this page and take it along to an appointment. Ask your GP to talk it through with you. You may be able to decide together whether you need to see a specialist and if so, how soon.
