Prostate Cancer
Contents:
Prostate cancer is caused by the uncontrolled growth of abnormal cells in the prostate gland. The prostate gland is about the size and shape of a walnut and is located just below the bladder. It surrounds the urethra which carries urine from the bladder to the penis. The prostate gland produces fluid that makes up part of the semen, the fluid gives ejaculate its milky colour. Though the prostate is part of the male reproduction system it's not clear how much of a role the prostate gland may play in fertility. Prostate cancer is a hormone dependent cancer, it depends on male hormones, primarily testosterone, to develop.
Women cannot get prostate cancer because they do not have a prostate.
Age
Prostate cancer is mainly found in older men. As men age they may experience problems with their prostate, it may get bigger and block the urethra or bladder. This may cause difficulty in urination or can interfere with sexual function.
BPH
BPH stands for Benign Prostatic Hyperplasia and Benign Prostatic Hypertrophy, two conditions common in older men. BPH is most likely to effect men over the age of 60. The prostate gland gets slowly bigger, causing difficulty or pain when peeing. BPH does not lead to cancer, or increase the risk of cancer developing. Surgery may be needed to correct it and often prostate cancer is discovered when patients undergo surgery for BPH.
PIN
PIN (Prostatic Intraepithelial Neoplasia) is a pre-cancerous condition that affects cells in the prostate. The cells that line the ducts of the prostate change and appear to imitate what happens in prostate cancer cells. Research suggests that like prostate cancer cells, PIN is dependent on the androgen hormone testosterone for its growth.
PIN is the most significant reason that men develop prostate cancer. It is thought that the presence of PIN can mean a fifteen times higher risk of developing prostate cancer compared to those without PIN.
PIN is not a disease. It does not have any symptoms and does not need treatment. PIN can only be diagnosed from the study of prostate tissue under a microscope making it inappropriate as a method of mass screening.
Family history of prostate cancer
It is thought that some people have a genetic predisposition to prostate cancer, but there may also be factors which bring it on earlier in life. Men with a family history of prostate cancer in a first degree relative have an increased risk of developing the disease. It has been estimated that a predisposing gene could be responsible for up to 10% of prostate cancer cases.
Family history of breast cancer
Men whose families have an increased risk of breast cancer also have a higher risk of prostate cancer.
Diet
There is some evidence to suggest that diet may affect the chances of developing prostate cancer. However there is little evidence that changing diet later in life can prevent prostate cancer.
Countries with a high level of heart disease tend to have high levels of prostate cancer. The diets in these countries often include high levels of fat which is linked to heart disease and may also increase the risk of prostate cancer. A high fat diet may affect the male sex hormone testosterone which controls the growth and function of the prostate.
People in Far Eastern countries such as China and Japan are less likely than Westerners to develop cancer. When people have migrated from Japan to the USA, the rate of prostate cancer in their descendants has greatly increased. Since their genetic make-up is largely the same the risk of prostate cancer is likely to be related to environmental factors such as diet.
Cadmium and Radiation exposure
Occupational exposure to high levels of cadmium and radiation exposure may increase the risk of prostate cancer, although studies are inconclusive.
Vasectomy
There is inconclusive evidence as to whether having a vasectomy increases the risk of prostate cancer.
Hormone deficiency
Men who are hormone deficient, either as a result of disease, treatment, or castration (e.g., testicular cancer, trauma, or sexual reassignment) do not develop prostate cancer.
Healthy diet
Excess fat in the diet should be avoided, it is better to bake, steam, poach and grill foods rather than use fat and oils. More fish and poultry should be eaten and red meat only occasionally. High fat snacks such as biscuits, crisps and chocolate should also be avoided.
Maintaining a normal weight generally indicates a healthy level of dietary fat.
Eat more Antioxidants
Antioxidants are found in most fruit and vegetables and may help to prevent prostate cancer. Antioxidants may stop the damage caused by free radicals; harmful molecules that occur in the body. Free radicals can cause cell damage and lead to diseases such as cancer and heart disease. Vitamin C, vitamin E and selenium are some of the more common antioxidants.
Five or more portions of fruit or vegetables a day ensure a diet rich in antioxidants.
Vitamin E supplements
A recent study in Finland found a reduction in prostate cancer deaths when vitamin E was given as a dietary supplement to men who smoke. However routine Vitamin E supplementation can not be recommended for all men as other studies have not shown the same benefits, in fact some studies have shown more deaths from strokes in those groups taking vitamin supplements.
It is recommended that diets should include a naturally occurring source of vitamin E. Rich sources of vitamin E are vegetable oils, vegetable spreads and nuts.
Selenium Supplements
Selenium supplementation was also found to reduce prostate cancer in a small group of men, but again the evidence is not yet strong enough to recommend routine supplementation.
A twelve-year study has just begun in the US to explore the links between Vitamin E and Selenium supplementation and a reduced risk of prostate cancer.
It is recommended that diets should include a naturally occurring source of selenium. Selenium can be found in fish, lentils and Brazil nuts.
Lycopene
Lycopene is an antioxidant found in tomatoes. Lycopene is the compound that gives tomatoes their red colour. There is some evidence from the USA that men who eat a lot of processed tomatoes, such as pizza toppings and pasta sauces, are less likely to develop prostate cancer. It is recommended that one tomato portion should be eaten a day, either as fresh or processed tomatoes.
The research on lycopene is just beginning and it may be that there are other nutrients in tomatoes that are also beneficial. It is better to increase the consumption of fruit and vegetables including tomatoes rather than take supplements.
Soya
Beans from which the soya protein is extracted contain compounds called isoflavanoids. The most well known of these is genistein. In the laboratory genistein has been shown to stop prostate cancer cell growth. Unfortunately, there is no evidence that this happens in humans. Overall inclusion of soya into the diet such as soya milk, soya yogurt or tofu could be beneficial.
Alcohol
Recent studies indicate that drinking alcohol has very little, if any, effect on the risk of prostate cancer and then only with very heavy alcohol consumption.
There is no national screening programme for prostate cancer in any European countries. Caught early on, prostate cancer is a very treatable disease. Unfortunately about half the men who are diagnosed with prostate cancer are diagnosed at a late stage when the disease is less treatable. Being aware of the signs that something might be wrong and going for regular health checks can help catch the disease before it becomes more serious.
PSA is the most reliable test to detect prostate cancer. The PSA test and a rectal exam can help to detect prostate cancer in men who detect the symptoms and visit a doctor.
Prostate-specific antigen (PSA) is a protein produced by the cells of the prostate gland. The PSA test measures the level of PSA in the blood. The higher a man's PSA level, the more likely it is that cancer is present. However there are many other possible reasons for an elevated PSA level which is why PSA testing is not recommended as a wide spread screening programme. European screening trials are being run to establish the best methods of screening for prostate cancer.
High grade PIN which can lead to prostate cancer does not need treatment. However the presence of high grade PIN increases the likelihood of developing prostate cancer and regular specialist consultation is recommended. The specialist may recommend prostate biopsy at three to six month intervals for two years, then yearly for life to monitor the development of PIN.
Symptoms of prostate cancer can include:
- Weak or interrupted flow of urine
- Frequent urination (especially at night)
- Difficulty urinating
- Burning or Pain during urination
- Blood in the urine or semen
- Irritating pain in the back, hips, or pelvis
- Painful ejaculation
The following tests may be used to diagnose prostate cancer.
Digital rectal exam (DRE)
An exam of the rectum by a doctor or nurse. A lubricated, gloved finger is inserted into the rectum through the anus (back passage) and the prostate is felt through the rectal wall for any lumps or abnormal areas.
Prostate-specific antigen (PSA) test
This is a test that measures the level of PSA in the blood. PSA is a substance made in the prostate, men who have prostate cancer have a higher amount of PSA in the blood. PSA levels may also be high in men who have an infection or inflammation of the prostate or an enlarged, but noncancerous, prostate. It also tends to be high in smokers.
Transrectal ultrasound
An endoscope (a thin, lighted tube) is inserted into the rectum via the back passage to check the prostate. The endoscope is used to bounce high energy sound waves off internal tissues or organs and make echoes. The echoes make up a picture called a sonogram.
Transrectal biopsy
Tissue is removed from the prostate by inserting a thin needle through the back passage and into the prostate. This is usually done using transrectal ultrasound to help guide the needle. A specialist can then view the tissue under a microscope to look for cancer cells and determine how likely it is that a tumour will spread. This is known as the Gleason score, the lower the number, the less likely the tumour is to spread.
Transperineal biopsy
Tissue is removed from the prostate by inserting a thin needle through the skin between the scrotum and rectum and into the prostate. A specialist can then view the tissue under a microscope to look for cancer cells and determine how likely it is that a tumour will spread.
After prostate cancer has been diagnosed, tests are done to find out if cancer cells have spread within the prostate or to other parts of the body. This is called staging and determines the stage of the disease.
Radionuclide bone scan
A procedure to check if there are cancer cells in the bone. A very small amount of radioactive material is injected into a vein and travels through the bloodstream. The radioactive material collects in any cancer cells in the bones and is detected by a scanner.
MRI (magnetic resonance imaging) or NMRI (nuclear magnetic resonance imaging)
Magnet, radio waves, and a computer are used to make a series of detailed pictures of areas inside the body.
Pelvic lymphadenectomy
A surgical procedure to remove the lymph nodes in the pelvis. A specialist views the tissue under a microscope to look for cancer cells.
CT scan (CAT scan)
A CT scan can help to show up tumours in the prostate and in other organs of the body. A series of detailed pictures are taken of areas inside the body from different angles. The pictures are made by a computer linked to an x-ray machine. A dye may be used to help make the organs or tissues show up more clearly.
Seminal vesicle biopsy
Fluid is removed from the seminal vesicles (glands that produce semen) using a needle. A specialist views the fluid under a microscope to find out if cancer is present.
The results of any tests carried out are looked at along with the results of the original tumour biopsy to determine the prostate cancer stage.
Four types of standard treatment are used to treat prostate cancer.
Watchful waiting
Watchful waiting is when a patient's condition is closely monitored without giving any treatment until symptoms appear or change. This is usually used in older men with other medical problems and early-stage disease. Men can often die with prostate cancer rather than because of it.
Surgery
Patients in good health who are younger than 70 years old are usually offered surgery as treatment for prostate cancer. The following types of surgery can be used:
Pelvic lymphadenectomy
A surgical procedure to remove the lymph nodes in the pelvis. A specialist views the tissue under a microscope to look for cancer cells. If the lymph nodes contain cancer, the doctor will not remove the prostate and may recommend other treatment.
Radical prostatectomy
A surgical procedure to remove the prostate, surrounding tissue, and nearby lymph nodes. There are 2 types of radical prostatectomy:
1/ Retropubic prostatectomy
A surgical process to remove the prostate through a small cut in the abdominal wall. Removal of nearby lymph nodes may be done at the same time.
2/ Perineal prostatectomy
A surgical process to remove the prostate through a small cut made in the perineum (area between the scrotum and anus). Removal of nearby lymph nodes may be done at the same time.
Transurethral resection of the prostate (TURP)
A surgical process to remove tissue from the prostate using a cystoscope (a thin, lighted tube) inserted through the urethra. This is sometimes carried out to relieve symptoms caused by a tumour before other cancer treatment is given.
Side effects of surgery
Men who have surgery to treat their prostate cancer may suffer from impotence and leakage of urine from the bladder or stool from the rectum. In some cases, doctors can use a technique known as nerve-sparing surgery. This type of surgery may save the nerves that control erection. However, in men with large tumours or tumours that are very close to the nerves it is not always possible.
Radiation therapy
Radiation therapy uses high-energy x-rays or other types of radiation to kill cancer cells. Radiotherapy for prostate cancer can be given to try and cure prostate cancer or treat prostate cancer that has spread. There are different ways of giving radiotherapy to try to cure prostate cancer.
One way is external beam radiotherapy, this treatment uses a high dose of radiation just to the area of the prostate gland.
Another form of radiotherapy is known as internal radiotherapy or brachytherapy. This treatment involves having very small radioactive 'seeds' put into the prostate. The seeds stay there and give a high dose of radiation to the prostate cancer over a few months. The radiation does not travel very far in the body so surrounding healthy tissue receives a much smaller dose than the prostate.
There is also internal radiotherapy using radioactive needles. The needles are placed into the prostate for a couple of days and then removed. This treatment may have to be done more than once.
Side effects of radiation therapy
Impotence and urinary problems may occur in men treated with radiation therapy.
Chemotherapy
Chemotherapy is a cancer treatment that uses drugs to stop the growth of cancer cells, either by killing the cells or by stopping the cells from dividing. Chemotherapy can be used for prostate cancer when the cancer has spread and has stopped responding to hormone therapy. It is not used very often to treat prostate cancer. The most widely used drug is called mitoxantrone.
Side effects of chemotherapy
Chemotherapy affects normal cells as well as cancerous cells and may cause side effects. Side effects vary with the dose and particular drug a patient receives, but common side effects include nausea, loss of hair, fatigue, diarrhoea, vomiting, fever, chills, coughing/shortness of breath, mouth sores, and skin rash. Long-term side effects may include dizziness, numbness, loss of reflexes, and difficulty hearing.
A rare side effect of some chemotherapy drugs is the development of another form of cancer, usually leukaemia.
Hormone therapy
Hormone therapy removes hormones or blocks their action and stops cancer cells from growing. Hormones are substances produced by glands, such as the prostate gland and are circulated in the bloodstream. Prostate cancer is hormone dependent and relies on androgen hormone testosterone to grow. If tests show that the cancer cells have places where hormones can attach (receptors), drugs, surgery, or radiation therapy are used to reduce the production of hormones or block them from working.
Hormone therapy used in the treatment of prostate cancer may include the following:
Luteinizing hormone-releasing hormone agonists can prevent the testicles from producing testosterone. Examples are leuprolide, goserelin, and buserelin.
Antiandrogens can block the action of androgens (hormones that promote male sex characteristics). Two examples are flutamide and bicalutamide.
Drugs that can prevent the adrenal glands from making androgens include ketoconazole and aminoglutethimide.
Orchiectomy is a surgical procedure to remove one or both testicles, the main source of male hormones, to decrease hormone production.
Estrogens (hormones that promote female sex characteristics) can prevent the testicles from producing testosterone. However, estrogens are not often used today in the treatment of prostate cancer because of the risk of serious side effects.
Side effects of hormone therapy
Hot flashes, impaired sexual function, and loss of desire for sex may occur in men treated with hormone therapy.
Cryosurgery or cryotherapy
Cryosurgery is a new treatment in development that uses an instrument to freeze and destroy prostate cancer cells.
Biologic therapy
Biologic therapy (also known as biotherapy or immunotherapy) is a new treatment in development that uses the patient's immune system to fight cancer. Substances made by the body or created artificially are used to boost, direct, or restore the body's natural defences against cancer.
World
- Worldwide over half a million men are diagnosed with prostate cancer each year.
- Over 200,000 people die each year.
- In many countries the incidence rates are rising rapidly with an annual increase worldwide of 1.7% over the past 15 years.
- The highest rates in the world are recorded in Afro American men.
- The lowest rates are reported in Far Eastern and Asian countries such as China, Japan and India.
Europe
- In Europe prostate cancer is the most common cancer in men after lung cancer.
- There are approximately 134,000 new cases every year.
- There are approximately 56,000 deaths each year in Europe from prostate cancer.
UK
- In the UK prostate cancer is the most common cancer in men after lung cancer.
- There are approximately 20,000 new cases in the UK each year.
- There are approximately 9,500 deaths from prostate cancer each year.
- 95% of all cases are in men over 60 years old.
Trends
The numbers of prostate cancers will rise as the population of those at risk (older men) grows.
Survival
Survival from prostate cancer is strongly related to the stage of the disease when it's diagnosed. A decrease in mortality has been seen in the USA since 1991 and in Europe overall since 1992. It is too soon to be able to draw conclusions as to why this has happened.
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