The main function of the prostate is to help in the production of semen. The prostate produces a thick white fluid that is then liquefied by a special protein known as prostate-specific antigen (PSA). The fluid is then mixed with sperm, produced by the testicles, to create semen.
Prostate cancer is the most common cancer in men. It is responsible for 25% of newly diagnosed cases of cancer in England and Wales.
The chances of developing prostate cancer increase as you get older. Most cases develop in men aged 65 or older.
For reasons that are not understood, prostate cancer is more common in men who are of Afro-Caribbean or African descent and less common in men of Asian descent.
The causes of prostate cancer are largely unknown.
The outlook for prostate cancer is generally good despite it being relatively challenging to treat. This is because, unlike many other cancers, prostate cancer usually progresses very slowly. It can take up to 15 years for the cancer to spread from the prostate to other parts of the body (metastasis), typically the bones. In many cases, prostate cancer won't affect a man's natural life span.
Once the cancer has spread to the bones it can't be cured, and treatment is focused on prolonging life and relieving symptoms. Approximately 9,000 men die from prostate cancer every year in England and Wales.
People who are at higher risk include:
- African-American men
- Men who are older than 60
- Farmers
- Tire plant workers
- Painters
- Men who have been exposed to cadmium
Symptoms of prostate cancer
Symptoms of prostate cancer include:- difficulty in starting to pass urine
- a weak, sometimes intermittent flow of urine
- dribbling of urine before and after urinating
- a frequent or urgent need to pass urine
- pain when passing urine
- rarely, blood in the urine
- erectile dysfunction
Causes of prostate cancer
The cause of prostate cancer isn't fully understood at present, but you are more likely to develop prostate cancer if:
- you're over 50
- you have close relatives who have had prostate cancer
- several women in your family have had breast cancer - you may have inherited a faulty gene which may increase your risk of prostate cancer
- you're African-Caribbean or African-American
- your diet is high in fat
- you're overweight
Diagnosis of prostate cancer
Prostate-specific antigen (PSA) testingThe main test for prostate cancer is the PSA (prostate-specific antigen) test, which looks for raised levels of PSA in the blood. Prostate cancer increases the production of PSA, so the test may be able to detect prostate cancer in its early stages.
However, the test is problematic:
- Up to 20% of men who do have prostate cancer will not have a raised PSA level;
- Over 65% of men with a raised PSA level will not have cancer. PSA levels tend to rise in all men as they get older.
Digital rectal examination
The next step to confirming a diagnosis of prostate cancer is a digital rectal examination (DRE). This can be done by your GP.
During a DRE, your GP will insert a finger into your rectum (back passage). The rectum is close to your prostate gland, so your GP is able to check to see if the surface of the gland has changed. This will feel a little uncomfortable but it should not cause you pain.
Prostate cancer can cause the gland to become hard and bumpy. However, in some cases, the cancer causes no changes to the gland and a DRE may not be able to detect the cancer.
DRE is also useful in ruling out benign prostatic hyperplasia, as this causes the gland to feel firm and smooth.
Biopsy
Your GP will assess the risk of you possibly having prostate cancer based on a number of factors, including your PSA levels, the results of your DRE and associated risk factors such as age, family history and ethnic group. If it is felt that the risk is significant you will be referred to a hospital to discuss the options of further tests.
The most commonly used test is known as a transrectal ultrasound-guided biopsy (TRUS).
During a TRUS biopsy, an ultrasound scanner (a machine that uses sound waves to build up a picture of the inside of your body) is used to study your prostate. This also allows the doctor to guide a needle through your rectum which is then used to take small samples of tissue from your prostate (biopsy).
The procedure can be uncomfortable and sometimes painful. You may be given a local anaesthetic to minimize any discomfort. The biopsy may also cause complications such as bleeding and infection.
Although it is much more reliable than a PSA test, a biopsy may miss up to 20% of cancers. Therefore, you may need to undergo another biopsy if your symptoms persist, or your PSA level continues to rise.
Gleason score
The samples of tissue from the biopsy are then studied in a laboratory. If cancerous cells are found, they can be studied further to see how quickly the cancer will spread.
This is done by giving the samples a grade, known as a Gleason score. The lower the score, the less likely the cancer will spread.
- a Gleason score of 6 or less means the cancer is unlikely to spread,
- a Gleason score of 7 means that there is a moderate chance of the cancer spreading, and
- a Gleason score of 8 or above means that there is a significant chance that the cancer will spread.
Treatment of prostate cancer
Your treatment for prostate cancer will depend on a number of factors, such as your age and whether the cancer has spread, and if so, how far. There are various treatments available. Some can have serious side-effects so it's important to speak with your doctor who will advise you on the best treatment for you.Active monitoring
Sometimes, particularly for slow-growing tumours, no treatment is the best course of action. This is often called active monitoring or watchful waiting. Your condition will be monitored closely with routine check-ups. Your doctor may start treatment if your tests show that the cancer is growing or causing symptoms.
Surgery
Surgery is a common treatment for prostate cancer. It's most suitable for otherwise healthy men (usually, those under 70) whose cancer hasn't spread beyond the prostate.
The most common technique is a radical prostatectomy. This is a major operation, which removes the whole of the prostate and some surrounding healthy tissue.
New surgical developments include keyhole surgery (a laparoscopic prostatectomy) where the prostate is removed through smaller incisions and robot-assisted surgery.
Radiotherapy
Radiotherapy uses radiation to destroy cancer cells. Techniques for treating prostate cancer include conformal radiotherapy (CRT), high-resolution intensity modulated radiotherapy (IMRT) and brachytherapy.
Hormone therapy
Hormone therapy blocks the action of the male sex hormone (testosterone) that helps cancer grow. This can slow the growth and spread of prostate tumours but won't kill the cancer cells.
Medical hormone therapies include goserelin (Zoladex) and bicalutamide (Casodex).
Alternatively, surgical hormone therapy involves removing your testicles, which permanently gets rid of the main source of testosterone. This operation is called an orchidectomy.
Chemotherapy
If hormone treatment stops working (hormone refractory cancer) your doctor may recommend chemotherapy. Drugs such as docetaxel (Taxotere) are used to destroy cancer cells.
Cryotherapy
This is surgery to freeze the prostate with liquid gas and kill cancer cells. This treatment may be used if you have a recurrent or refractory prostate cancer.
Ultrasound
High intensity focused ultrasound (HIFU) is a treatment given using a machine that gives off high frequency sound waves. This heats up the targeted cancer cells and destroys them.
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