What is Prostate Cancer?
Prostate cancer starts in the cells of the prostate. The prostate is part of a man’s reproductive system. Its main function is to make part of the liquid (seminal fluid) that mixes with sperm from the testicles to make semen. Semen is ejaculated during sex.
The prostate is a walnut-sized gland just below the bladder and in front of the rectum. It surrounds part of the urethra, the tube that carries urine and semen through the penis.
Prostate cancer is the most common cancer in Canadian men. It usually grows slowly and can often be cured or managed successfully.
Read more: http://www.cancer.ca/en/cancer-information/cancer-type/prostate/overview/?region=on#ixzz2YNSf6cz7
About Prostate Cancer
Prostate cancer is the most common cancer among Canadian men (excluding non-melanoma skin cancer). Yearly:
- An estimated 25,500 men will be diagnosed with prostate cancer and 4,400 will die of it. One in 7 will develop prostate cancer during his lifetime (the risk is highest after age 60) and one in 27 will die of it.
- On average, 490 Canadian men will be diagnosed with prostate cancer every week.
- On average, 85 Canadian men will die of prostate cancer every week.
Early Detection of Prostate Cancer
When prostate cancer is detected and treated early, the chances of successful treatment are better. Recognizing symptoms and getting regular checkups are the best ways to detect prostate cancer early. The sooner symptoms are reported, the sooner a doctor can diagnose and treat the cancer.
Men over the age of 50 should talk with their doctor about whether they should have testing for early detection of prostate cancer. The following tests may be used to help detect prostate cancer early:
DRE is the most common way to check for prostate cancer.
Most prostate cancers develop in the peripheral zone of the prostate. The peripheral zone is the part of prostate that is closest to the rectum and can easily be felt by the doctor during a DRE.
A normal prostate feels smooth and rubbery. The doctor feels for lumps and changes in the size, shape and consistency of the prostate. Prostate cancer can feel like a hard or lumpy area.
The PSA test helps detect problems with the prostate, including prostate cancer.
It measures the amount of prostate-specific antigen in the blood.
The prostate makes PSA. It is normal to find small amounts of PSA in the blood, but problems with the prostate can cause the PSA level to rise.
A PSA test may find abnormalities in the prostate better than DRE, but it isn’t a perfect test for detecting prostate cancer.
Sometimes, high levels of PSA are caused by problems other than prostate cancer, and men with prostate cancer do not always have high levels of PSA.
Using these tests together is better than using either test alone, so these 2 tests are often used in combination. A DRE and PSA test can help detect prostate cancer early, but they are not 100% accurate. They can sometimes miss prostate cancer when it is present (false negative) or cause false alarms by suggesting that prostate cancer is present when it isn’t (false positive). In some cases, these tests can detect prostate cancer that may not pose a serious threat to a man’s health. Some prostate cancers grow very slowly and can be present for years without affecting a man’s health.
Research currently shows that the risks of testing for prostate cancer may outweigh the benefits of screening men at average risk of developing prostate cancer.
It is important for men to talk with their doctor about their personal risk of developing prostate cancer and about the benefits and risks of testing.
High-risk individuals
Men who are at higher than average risk of developing prostate cancer may need to be tested at an earlier age than people with average risk. Examples of what puts a person at higher than average risk include:
- African ancestry
- family history of prostate cancer
Men who are at higher than average risk should talk to their doctor about a personal plan for testing.
Risk factors for prostate cancer
From Canadian Cancer Society
http://www.cancer.ca/en/cancer-information/cancer-type/prostate/risks/?region=on
Any substance or condition that increases cancer risk is referred to as a risk factor. There isn’t a known, single cause of prostate cancer. Most cancers are the result of many risk factors. However, some people with prostate cancer do not have any identifiable risk factors.
| Risk factors* | Possible risk factors | Factors not associated with prostate cancer |
| Family history | Diets high in fat diets high in red or processed meats diets high in milk and dairy products inherited gene mutations inflammation of the prostate (prostatitis) circulating (endogenous) testosteroneExposure to pesticides | Benign prostate hyperplasia vasectomy frequency of sexual activity and ejaculation Alcohol |
*Risk factors are generally listed in order from most significant to least significant. In most cases, it is impossible to rank the relative significance of individual risk factors with absolute certainty.
The risk of prostate cancer increases as men grow older. Prostate cancer is not very common in men under 50 years of age. The chance of having prostate cancer increases after 50 and is diagnosed most often in men over the age of 65.
Men of African ancestry have a higher risk of developing prostate cancer. They have about a 60% higher rate of prostate cancer than Caucasian men. Men of African ancestry are more likely to be diagnosed at a younger age and with more aggressive and advanced tumours.
Men of Asian ancestry have lower rates of prostate cancer. The reason for these ethnic differences is not clear.
The following factor is known to increase the risk of developing prostate cancer.
Family history
The risk of developing prostate cancer is higher if a first-degree relative (such as a father or brother) has been diagnosed with the disease. Men are at the highest risk if more than 1 relative has been diagnosed. The more first-degree relatives with prostate cancer a man has, the greater his risk of developing prostate cancer.
Risk is also influenced by the relative’s age at diagnosis. If a man’s relative was diagnosed with prostate cancer before the age of 65, his chance of developing prostate cancer is higher than if his relative was diagnosed at an older age.
Possible Risk Factors
The following factors have some association with prostate cancer, but there is not enough evidence to say they are known risk factors. Further study is needed to clarify the role of these factors for prostate cancer.
- diets high in fat – A diet high in fat, especially animal fat, may increase the risk of prostate cancer. Milk and dairy products contain animal fat. Some studies have suggested that men who eat large amounts of dairy products may have a slightly higher risk for prostate cancer. More studies are needed to determine how a high-fat diet or eating a lot of dairy products affects prostate cancer risk.
- diets high in red or processed meats – Some studies have shown that red meat, especially when it is cooked at high temperatures, and processed meat may increase the risk of developing prostate cancer. White meat intake did not increase prostate cancer risk.
- diets high in milk and dairy products – Milk and dairy products contain animal fat, which may increase the risk of prostate cancer. Some studies have also suggested that men who eat larger amounts of dairy products may have a increased risk for prostate cancer. Milk is a good source of calcium, and some studies have suggested that a high calcium intake may increase the risk of developing prostate cancer.
- inherited gene mutations – Studies have found that some inherited gene mutations may increase the chance of developing prostate cancer. However, cancers associated with these gene mutations account for only a very small number of cases of prostate cancer. Men who inherit mutations of the BRCA genes may have a higher risk of developing prostate cancer. These genes also increase a woman’s risk of developing breast or ovarian cancer. Researchers are also studying other gene mutations that may affect the risk of developing prostate cancer.
- inflammation of the prostate (prostatitis) – Many studies have shown that long-term inflammation of the prostate gland (prostatitis) increases the risk of developing prostate cancer. It also increases the rate at which prostate cancer grows and spreads.
- circulating (endogenous) testosterone – Long-term exposure to higher levels of testosterone and its metabolite dihydrotestosterone (DHT) may increase the chance of developing prostate cancer.
- Testosterone is the main male hormone (androgen) responsible for the growth and functioning of the prostate gland.
- The actual role of testosterone in the development of prostate cancer is complex.
- Some evidence suggests that androgens are related to the growth and development of prostate cancer. Hormonal therapy that blocks the body’s production of these hormones is one of the treatments for prostate cancer.
- exposure to pesticides – Studies have suggested that farmers and workers who spray pesticides have a slightly higher risk of developing prostate cancer. The risk may be higher for men with a family history of prostate cancer. It is not known which specific chemicals may be responsible for this increased risk. Pesticides have a large number of different chemicals, only some of which may be related to prostate cancer.
- occupational exposures – Some evidence suggests that occupational exposure to some chemicals may increase the risk for prostate cancer.
- cadmium exposure – Cadmium is a metallic element known to cause cancer. Some studies have shown that men exposed to cadmium in smelting or battery manufacturing industries had a higher risk of developing prostate cancer. Further research is needed to determine how cadmium exposure affects prostate cancer risk.
- rubber manufacturing – There is some evidence that workers in the rubber manufacturing industry have an increased risk of developing prostate cancer.
Factors Not Associated with Prostate Cancer
The following are not considered to be risk factors for prostate cancer because there is enough evidence showing that there is no association:
- benign prostate hyperplasia
- vasectomy
- frequency of sexual activity and ejaculation
- alcohol
Unknown Risk Factors
The following are factors for which there is not enough evidence or the evidence is inconclusive. In other words, it can’t be determined for sure whether these risk factors are or are not associated with prostate cancer.
- testosterone therapy (exogenous)
- Men who take testosterone as a therapy and who have high levels of testosterone in their blood do not seem to have a higher risk of developing prostate cancer.
- sexually transmitted infections (STIs)
- Some studies have shown that men with a history of sexually transmitted infections (STIs) may be at higher risk of developing prostate cancer.
- Evidence supporting this association has not been consistent and, to date, no specific infectious agent that increases the risk has been identified.
- Further research is needed to understand the role that STIs may play in prostate cancer development.
- obesity
- Some studies have shown that obesity (a body mass index of 30 or more) may increase the risk of prostate cancer.
- Other studies did not have the same findings. It is not clear whether there is an association between obesity and prostate cancer risk.
- Further study is needed to understand the complex role of obesity in prostate cancer development.
- lack of physical activity
- Research looking for a connection between physical activity and the risk of prostate cancer has not been consistent.
- More studies are needed to find out if men who are not very physically active have an increased risk for prostate cancer or if men who are physically active have a decreased risk.
- sedentary behaviour
- Sitting for long periods of time (sedentary behaviour) has been linked to an increased risk for prostate cancer. The evidence around sedentary behaviour on cancer risk is new and still emerging and further study is needed to clarify its role in prostate cancer development.
- low levels of dietary nutrients
- Some studies have suggested that men with low levels of dietary nutrients, such as vitamin D, vitamin E or selenium, may have higher rates of prostate cancer. However, the results of other studies have not been conclusive.
- Studies have shown that taking supplements of these nutrients do not reduce the risk of prostate cancer.
- More research is also needed to determine what role supplements play and if they reduce prostate cancer risk. Men should talk to their doctor if they are concerned about not getting enough nutrients.
Trends in Prostate Cancer
There has been an overall upward trend in the incidence rate of prostate cancer since 1980, which is likely due to increased early detection or possible changes in risk factors. Death rates rose much more slowly during the same period and started to decline in the mid 1990s, which is likely due to earlier detection and better treatments.
