A cancerous tumour arising from the glandular tissue of the prostate gland
- Rare under the age of 40; increasingly common over the age of 65
- Sometimes runs in families; more common in certain ethnic groups
- Lifestyle is not a significant factor
Prostate cancer is the most commonly diagnosed male cancer in the UK, affecting about 1 in 10 men at some time in their lives. The disorder is more common in northern Europeans and black men, but it is rare in men from Asian countries. The number of cases of prostate cancer identified in the UK has been rising since the 1970s, not only in elderly men, in whom it is most common, but also in men in their 40s and 50s. This increased identification in recent years has been largely due to increased public awareness and the availability of a screening test that measures the level of a protein called prostate-specific antigen, secreted by the prostate gland. Although prostate cancer is the cause of about 10,000 deaths each year in the UK, many tumours grow slowly, especially in elderly men, and may never cause symptoms. Treatment is more likely to be necessary in younger men.
What are the causes?
The exact cause of prostate cancer is not known, although the male sex hormone testosterone, produced by the testes, has been found to influence the growth and spread of the tumour. In about 5 to 10 per cent of cases, the cancer is partly due to an inherited abnormal gene. In these cases, it is more likely to occur before the age of 60. Although there has been concern that having had a vasectomy increases the risk of prostate cancer, there is no firm evidence to support this view.
What are the symptoms?
Prostate cancer may not produce any symptoms, particularly in elderly men. If symptoms do occur, they are likely to develop when the tumour starts to constrict the urethra. The symptoms may then include:
Weak urinary stream or inability to pass urine normally.
Frequent urge to pass urine, especially during the night.
Rarely, blood in the urine.
In some men, the initial symptoms of prostate cancer are due to the metastasis (spreading) of the cancer to other parts of the body, most commonly the bones, lymph nodes, and lungs. In these cases, the symptoms may include back pain, enlarged lymph nodes, shortness of breath, and significant weight loss.
How is it diagnosed?
If you develop the symptoms of prostate cancer or if the disorder runs in your family, you should consult your doctor. The doctor will perform a digital rectal examination, in which a finger is inserted into the rectum to feel the prostate gland. He or she may also arrange for a blood test to measure your prostate-specific antigen levels.
You may be referred to hospital to have a type of ultrasound scanning in which a probe is inserted into the rectum to visualize the prostate gland. This procedure enables the doctor to assess the size of the gland and to look for any abnormalities. During scanning, a prostate gland biopsy may also be carried out. In this procedure, some cells are removed from areas of the gland that appear abnormal and are examined under a microscope. If prostate cancer is diagnosed, you may need imaging tests, such as MRI and radionuclide scanning, to check whether the prostate cancer has spread to other parts of the body.
What is the treatment?
The choice of treatment depends on age, general health, and whether the cancer has spread to other parts of the body. If the cancer is confined to the prostate and your health is otherwise good, your doctor may recommend that the entire prostate gland be surgically removed, along with some of the surrounding tissues (see Radical prostatectomy). Alternatively, radiotherapy may be given. This form of therapy involves either having a radioactive implant or radioactive seeds placed in the prostate gland or undergoing external radiotherapy over several weeks. In elderly men in whom the cancer is confined to a small area of the prostate gland, no immediate treatment may be required, but the course of the disease will be closely monitored.
If the cancer has spread beyond the prostate, a cure may not be possible. However, progress of the disease can be slowed significantly with hormone ablation therapy. In this treatment, drugs that block the release or actions of testosterone are given to suppress the effects of the hormone on the cancer (see Drugs for prostate disorders). In some cases, part of both testes may be surgically removed to stop the production of testosterone. Rarely, treatments that block the actions or production of testosterone result in erectile dysfunction and loss of interest in sex.
What is the prognosis?
A diagnosis of cancer of the prostate gland does not necessarily mean that the cancer will cause symptoms or be life-threatening. Sometimes the best policy, especially in elderly men, is to defer treatment and begin regular checkups to monitor the disease. Men with certain types of small tumour do not need treatment and are likely to live for several years with no symptoms before dying from some other cause. For men who have had surgery for a tumour confined to the prostate gland, the outlook is good, with about 9 out of 10 men surviving for at least 5 years after diagnosis. However, surgery may result in erectile dysfunction and urinary incontinence.
Cancer that has spread beyond the prostate is unlikely to be cured completely, but hormone ablation therapy often controls the symptoms for years.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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