Prostate cancer is caused by both genetic and environmental factors. Learn about the causes and treatments.
Medically reviewed by Dr Louise Wiseman MBBS, BSc (Hons), DRCOG, MRCGP and words by Chris Dawson (MS FRCS LLDip)
Prostate cancer is the most common cancer in men in the UK. The chances of developing prostate cancer increase as you get older, so most cases develop in men aged 65 or above although it can occur at a much younger age.
Around 47,000 men in the UK are diagnosed with prostate cancer each year, with it affecting about 1 in 8 men at some time in their lives. Sadly, approximately 11,700 British men die of prostate cancer every year, so it’s a disease that needs to be taken very seriously.
What is prostate cancer?
It involves the prostate gland, which is a small gland about the size of a walnut, positioned just between the penis and the bladder surrounding the urethra, the tube along which urine passes. The prostate is responsible for producing fluids that nourish and protect sperm.
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At present evidence does not support a role for routine screening for prostate cancer.
Why does prostate cancer happen?
It is still not entirely clear why some men develop prostate cancer and others do not.
However, we do know that there are both genetic and environmental factors that can influence it.
In terms of genetic factors, you have a higher risk of developing prostate cancer if your father or brother had prostate cancer before the age of 60, although the increased risk is still relatively small.
Perhaps more important are environmental factors such as diet and lifestyle.
Regularly eating foods high in animal fat may increase risk and a diet high in vegetables, fruits and legumes may reduce risk but more studies are needed to quantify this.
When we look at geographical differences, people living in the Far East, such as the Chinese and Japanese, have an extremely low risk of developing prostate cancer compared with those who live in Western countries such as Northern America and Northern Europe. However, prostate cancer is increasing in Asian men living in urbanised areas such as Hong Kong, Singapore, North American and European cities, suggesting that lifestyle plays a strong role. These men may follow the lifestyle of the areas in which they settle with potentially less activity and a less healthy, more processed diet. As a general point overall however, prostate cancer is more common in African-Caribbean men, and less common in men of Asian origin.
Scientists are currently investigating whether certain dietary factors may help to prevent prostate cancer. Much of this work is focusing on the mineral selenium, and a substance from processed tomatoes called lycopene.
Several studies have suggested that both these agents lower the risk of developing prostate cancer but we need further investigation.
The relationship between smoking and prostate cancer is controversial but it does seem from a review study that smoking can worsen the progress of aggressive prostate cancer or reduce the effectiveness of treatment. More recent discussions of the topic still suggest that smoking is linked to worse outcomes in the disease.
You cannot catch prostate cancer through sex, nor can you infect your partner with prostate cancer.
Vasectomy was once thought to predispose men to prostate cancer but studies have suggested if there is an increased risk it is very low relatively and may be dependent on other factors as well. More studies are needed.
Prostate cancer generally takes a long time to progress and it can take 10 years before it is detected. But some men have a particularly aggressive form of the disease, and the disease can grow and spread more quickly.
Prostate cancer symptoms
Most cases of early prostate cancer do not produce any symptoms at all – therefore the absence of any urinary symptoms does not rule out the presence of prostate cancer.
As men get older the prostate tends to enlarge (benign prostatic hyperplasia) and if the prostate gland grows significantly, it can put pressure on the urethra and this may cause various problems.
Common symptoms of benign prostatic hyperplasia (BPH) include:
- frequent visits to the bathroom to pass urine (frequency)
- having to wake up regularly throughout the night to pass urine (nocturia)
- a sense of urgency in getting to the bathroom in time (urgency)
- hesitation before the urine begins to flow (hesitancy).
It’s important to emphasise that the presence of such symptoms does not necessarily mean you have prostate cancer as most men with these symptoms do not.
However, if you do have any of these symptoms, please consult your doctor for advice.
Prostate cancer diagnosis
There are three tests that can help to diagnose prostate cancer.
Firstly, a test will be carried out to measure levels of prostate-specific antigen (PSA) in the blood. The other test that can be carried out is a digital rectal examination.
PSA is a protein produced by the prostate gland. All men have a small amount of PSA in their bloodstream (up to around 4ng/ml). If this level rises your GP may wish to refer you to a urologist for further tests.
A digital rectal examination involves the doctor placing a finger inside your back passage and feeling the prostate gland to check its size and shape and whether any lumps can be detected. Although not very pleasant, this should not hurt in any way.
Although neither test is 100 per cent accurate, taken together with your age they can allow your specialist to assess your risk of having prostate cancer.
Your doctor may also take into account any family history of prostate cancer.
What else could it be?
A raised PSA does not necessarily mean that you have prostate cancer. Almost any condition that causes the prostate gland to grow or swell will result in a raised PSA test result. PSA can also be raised with a urinary tract infection or any benign inflammation of the prostate, so we say it is a non-specific test.
PSA also rises slightly naturally as you get older. Similarly, a digital rectal examination can be very difficult to interpret and may require the expertise of a doctor with specialised knowledge.
What can your doctor do?
If a prostate gland feels large and smooth on a digital rectal examination, then this generally indicates benign prostatic hyperplasia, which is not life threatening and can be treated in many ways. However, if it feels lumpy, there may be cause for concern and this will require further tests.
Equally, the PSA result can be high in men with benign prostatic hyperplasia or prostatitis as well as in those with prostate cancer. Most urologists now use age-specific reference values for PSA that take account of a small rise in PSA with age.
Always take a pen and notepad (or perhaps your partner or friend) to the consultations that you have with your doctor. This will enable you to remember what has been said to you and will help you discuss your condition with others later on.
In men with either an abnormal feeling prostate or a PSA raised above the age-specific reference value, a referral is usually made to a specialist known as a urologist. The urologist will discuss the risk of prostate cancer with you in more detail.
In some cases a trans-rectal ultrasound of the prostate and biopsy of the prostate will be recommended. Here, a small ultrasound probe is placed inside the back passage, which provides an image of the prostate gland and its surrounding tissue. The urologist can then insert a biopsy needle into the prostate gland under local anaesthetic to take small biopsy samples.
This tissue can then be analysed under a microscope to give a much clearer understanding of the cause of the problem. You will be given antibiotics during this time to prevent any possible infections after the biopsy.
You may also notice a small amount of blood in your urine or faeces. This is not usually a problem, but if it persists you must consult your doctor.
Sometimes blood may be noticed in the semen after a prostate biopsy, and this may persist for up to 6 to 8 weeks but usually settles without specific treatment.
One further source of uncertainty relates to the results of the prostate biopsy. If the biopsy shows prostate cancer then this will be discussed with you in detail. This is covered in the section below.
Whilst a negative biopsy is reassuring, it does not exclude prostate cancer completely – sometimes prostate cancers are very small and unless the needle biopsy passes through the area of cancer, it will not show up on the biopsy results. This can lead to some uncertainty and anxiety.
Normally the doctor will suggest surveillance with a further PSA blood test after 4 to 6 months. If the PSA rises further after this time then further biopsies may be required.
Because of these issues with prostate biopsies, the current NICE guidelines now recommend performing an MRI Scan of the prostate gland as a first-line specialist investigation for people with suspected clinically localised prostate cancer, and this should be performed before any biopsy.
Prostate cancer treatment
If prostate cancer has been detected in the biopsy specimens, you now have several difficult choices to make with regard to treatment.
The way the disease is treated depends on many factors, including your age and the size and grade of your cancer.
The biopsy specimen is often given a score known as the Gleason Score. Evidence has shown that the Gleason score (a measure of the ‘aggressiveness’ of the tumour) is closely linked to the risk of dying from the prostate cancer.
Under the microscope, the pathologist looks at all the areas on the biopsies that show cancer and gives a Gleason grade of between 1 and 5 to each of the two most common patterns seen.
Grade 1 is the least aggressive and Grade 5 is the most aggressive. These grades are then added together to give a Gleason score which may be phrased as (for example) Gleason 4+3, or Gleason 7.
Cancers with a Gleason score of between 2 and 6 can often be managed by active surveillance as this is a low-grade cancer. Essentially this means repeating the PSA at frequent intervals (usually every 4 to 6 months) and then having further biopsies or scans after a year of surveillance.
The main advantage of active surveillance is the avoidance of any of the complications associated with active treatments (see below), but some patients find the uncertainty associated with the surveillance process too difficult.
A Gleason score of 7 suggests the cancer will grow moderately quickly and a score of 8 to 10 is a high-grade cancer that usually grows most quickly of all.
Cancers localised to the prostate
Other than active surveillance these cancers are normally suitable for treatment either with surgery, radiotherapy or brachytherapy.
For localised cancers (those which are contained), it’s possible to remove the entire gland in an operation called a radical prostatectomy.
In the past this operation involved the surgeon making an incision in your lower abdomen and taking out the whole prostate gland. Recent advances in laparoscopic (telescopic) surgery mean that most cases are now done with robotically.
This is a tricky operation and requires a very skilled surgeon to avoid cutting through the nerve bundles that surround the prostate gland. Because of the likelihood of some nerve damage, impotence is a common problem, and around 70 per cent of men will not be able to achieve a natural erection after the operation.
Because laparoscopic surgery uses only small incisions the recovery from surgery is much quicker than it used to be with ‘open’ surgery.
There’s also a slight risk of incontinence, with around 3 to 5 per cent of men requiring the long term use of incontinence pads.
This technique can also be used to treat contained cancers. It can be done in several ways. In external beam radiotherapy, radioactive beams are aimed at the prostate from outside the body.
However, radiotherapy beams cannot distinguish between normal and cancerous cells, so the beams need to be focused very carefully on the prostate gland itself.
A newer method, known as 3D conformal radiotherapy, is now used in many hospitals.
This technique involves feeding the co-ordinates of the prostate (size, shape, position) into a computer, which then shapes the beams to fit the prostate to limit the damage to normal tissue.
There are fewer side-effects with this treatment, with around 60 per cent of men becoming impotent and around 1 per cent of men experiencing incontinence.
There’s also a 5 per cent risk of developing bowel related symptoms, such as bleeding from the back passage, frequent or painful opening of the bowels. These symptoms can be long term.
This is type of radiotherapy involves placing radioactive seeds inside the prostate gland itself, thereby delivering radiation directly to the cancer.
In this procedure, the doctor inserts needles into the prostate gland under anaesthesia and then passes the seeds through the needles into the gland, where they remain forever. The seeds eventually lose their radioactivity and become ineffective. Because there’s no need for surgery, the procedure can generally be carried out in a day or two, and you should be able return to normal life immediately.
Around 3 in 10 men will become impotent after brachytherapy, and a small number of men will experience a burning sensation while urinating, although this normally disappears within weeks.
Brachytherapy in its current form is a relatively new technique, but new studies have monitored men for 10 years and found it to be comparable to surgery in its ability to destroy the cancer.
Cancer that has spread from the prostate
If the cancer has already spread from the prostate gland by the time it has been detected, it will normally be treated with hormone therapy. Prostate cancers require the male hormone testosterone to grow and spread. Therefore, if you deprive the cancer of testosterone, the cancer is starved.
Hormone therapy does just that, and although it will not completely remove the cancer, it can place it on hold for several years and can relieve a number of symptoms including bone pain and urinary problems. Hormone therapy can also be used in men whose cancer has spread slightly, because this treatment can kill some of the cancer and will shrink the remaining gland, making it easier to then be treated with either surgery or radiotherapy.
Hormone therapy can cause side-effects the most common of which is ‘hot flushes’ (similar to the ones experienced by women during the menopause).
There are two main groups of medicines available in this group – those that block testosterone and those that work on the pituitary gland in the brain.
Testosterone – blocking (anti-androgen) tablets include cyproterone and flutamide.
The pituitary gland makes a hormone which encourages testosterone production. Treatments that block this include goserelin, leuprorelin and triptorelin and are given either by implants under the skin or by injection.
Chemotherapy can also be used as a treatment for prostate cancer, as can a very new treatment called HIFU (high-intensity focused ultrasound) although this is not widely available yet in all hospitals.
How do you live with prostate cancer?
Ironically, prostate cancer itself may not cause you too many problems, whereas the treatment of the disease itself may do.
Many men are diagnosed through screening tests and have no symptoms at all until they are subsequently treated.
The most common problems resulting from treatment are impotence and incontinence. However, a diagnosis of cancer is enough to frighten anybody, so you may well experience some psychological effects such as depression.
In most men, impotence can now be treated very effectively with various therapies.
It’s important to ask your specialist about the risk of impotence if you would like to maintain a physical relationship. Your doctor can also refer you to an impotence adviser who can help you to find the most suitable treatment for you and your partner.
Incontinence can be more difficult to manage and men often resort to wearing incontinence pads.
However, there are other devices, and your doctor can refer you to an incontinence nurse, who will help you find the best solution to the problem. In extreme cases, it’s also possible to have a surgical operation to minimise incontinence.
Above all, there is no right or wrong way to deal with your diagnosis.
If you feel like sharing your experiences with somebody, there are plenty of organisations and support groups that can provide extra information for you, your family and even your friends.
If desired, they can also put you in touch with other men with the condition. It’s important to become informed about this disease before you select a treatment. By arming yourself with knowledge of the various pros and cons of each treatment, you can make an informed choice that is right for you.