The prostate gland is located just below the bladder. It is only found in men and is responsible for helping to produce the fluid found in semen. The gland is tiny at birth, but grows in size after puberty due to rising levels of the male hormone, testosterone. It is surrounded by a thin capsule and is situated in the pelvis, the lower part of the trunk between the abdomen and the thighs.
The prostate also has structures called the seminal vesicles attached to it (see diagram above). The seminal vesicles secrete around 60% of the fluid that ultimately becomes male semen.
What is testosterone?
Testosterone is the male sex hormone and around 90% of testosterone is produced in the testicles. It is essential to the development of the male reproductive organs and other male characteristics such as:
- body and facial hair
- low voice
- muscle development
- the ability to have an erection
- sex drive (libido)
- well being
What causes prostate cancer?
Prostate cancer occurs when normal, healthy cells, which are carefully regulated in the body, begin to reproduce uncontrollably in the prostate gland. In most cases the growth is slow, and the cancer can go undetected for many years because it may cause very few symptoms. In some cases, however, prostate cancer can progress more quickly and may spread to other parts of the body; however this still tends to be at a slower rate than other cancers.
What are the risk factors?
Prostate cancer mainly affects men over the age of 60 and it is generally thought that the majority of men in their 80s will have abnormal cells in their prostate gland.The most common age for a man to be diagnosed is in his mid-70s while it is rare in men under the age of 50 years.
Family history of prostate cancer
Having a brother or father with prostate cancer increases a mans risk by approximately 2-fold compared to men with no family history of the disease. The risk for a man if a second degree relative has been affected is slightly lower.If a man has both a first and second degree relative affected by prostate cancer this may increase the risk by 4-fold.
More than 1,000 men under the age of 55 years are diagnosed with prostate cancer each year in the UK. Up to 10% of these “early-onset” cases of prostate cancer are thought to be caused by inherited (genetic) forms of the condition.
What are genes?
Genes carry information in the form of DNA within each cell of the human body. They control how long a cell remains healthy and produce proteins that control specific tasks within the cell. For a body to remain healthy therefore each gene needs the correct instructions to function. There are thought to be around 30,000 different genes in each cell and these are packaged into chromosomes with 23 pairs of chromosomes in each of the body’s cells. One chromosome is inherited from a person’s father and one from a person’s mother. Many cancers appear to begin when one or more of the genes within the cell receive the wrong information and cause the cells to multiply abnormally and become cancerous.
Family history of breast cancer
The risk of prostate cancer increases slightly in men who have a strong family history of female breast cancer and vice versa (National Cancer Institute). This is thought to be because two genes carried by both men and women (called BRCA1 and BRCA2) as well as increase the risk of breast cancer in women and prostate cancer in men.
Men of African-Caribbean descent are more likely to develop prostate cancer than Caucasian men and are more likely to die from the condition. Prostate cancer in this group of men can be potentially more difficult to treat if not diagnosed at an early stage and may potentially require more treatment. No one is certain of why men in this group are more at risk of prostate cancer.
For more information on the risk of prostate cancer and black men please see:
The lowest rates of prostate cancer are found in Asian men. Interestingly however past research has indicated that when men of this ethnicity adopt a western lifestyle, they are at the same risk of developing prostate cancer as Caucasian men. This may indicate a strong lifestyle or dietary related factor in prostate cancer.
Diet and exercise
A diet high in saturated fats and red meat is thought to lead to an increased risk of developing several cancers, including prostate cancer. Conversely research has shown that some foodstuffs may offer some protection in reducing the risk of prostate cancer. However no one is sure how long in life it takes to build up this protection.
In general a healthy balanced diet such as the Mediterranean diet (see below) appears to be beneficial for good health in general. This is based on the type of diet eaten in southern European countries. The Mediterranean style diet relies less on red meat and more on fresh fruit, vegetables, fish and olive oil. Regular exercise in combination with this diet also appears to reduce health problems. Some recent research has also indicated that this type of diet may be beneficial for men who have prostate cancer that has not spread to other areas of the body (metastasised) in reducing their overall mortality from the disease.
For NHS guidelines on a healthy exercise plan for different age groups see here
What are the symptoms of prostate cancer?
There is no single symptom to indicate the presence of prostate cancer. Problems with the prostate are common, particularly as men get older and they may not necessarily be caused by cancer. They can easily be confused with “getting older”.
In fact many men with early prostate cancer may have no symptoms at all.
Because the prostate gland surrounds the tube known as the urethra, which passes urine from the bladder to the outside of the body, any prostate disease or growth (benign or malignant) is likely to cause problems with urination. However most prostate cancer is found in a particular area of the prostate gland known as the peripheral zone which is situated away from the urethra and so abnormal symptoms may not be present.
Symptoms of prostate cancer may include the following:
- Slow or weak flow of urine
- Urinating more frequently or urgently than usual
- Difficulty starting to urinate
- Pain or burning sensation when urinating
- Unexplained urinary infection
The above symptoms can also be caused by the prostate gland obstructing the bladder due to benign prostate enlargement which can in turn affect the nerves and muscles which control urination.
- Difficulty getting or maintaining an erection or pain during ejaculation
The above symptom can also be caused by age, diabetes, heart or cardiovascular disease.
- Constipation, altered bowel habit
The above symptom can also be caused by age, low intake of fibre, bowel problems such as diverticulitis and a benign prostate gland putting pressure on the rectum.
Less common symptoms can include the following:
- Blood in the urine or semen (blood in the semen can also be caused by non-cancerous conditions including infection or inflammation of the prostate gland)
- Pain in the back with no obvious cause or improvement with pain killers due to possible prostate cancer that has spread undetected to bones.
If you are experiencing any of the above symptoms and are worried that they could be related to prostate cancer please discuss them with your GP.
For further information on prostate cancer please see the NHS Choices link here
Last reviewed 15/2/16 Next review 15/8/16
References available on request.