Risk factors for prostate cancer
A risk factor is something that increases the risk of developing cancer. It could be a behaviour, substance or condition. Most cancers are the result of many risk factors. But sometimes prostate cancer develops in men who don’t have any of the risk factors described below.
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. It is diagnosed most often in men over the age of 65.
Men of Asian ancestry have lower rates of prostate cancer, while men of African ancestry have a higher risk of developing prostate cancer. Men of African ancestry have higher rates of prostate cancer and are more likely to be diagnosed at a younger age than Caucasian men. Men of African ancestry also tend to have more aggressive tumours that are diagnosed at an advanced stage. The reason for these ethnic differences is not clear.
Risk factors are generally listed in order from most to least important. But in most cases, it is impossible to rank them with absolute certainty.
*You may wonder about alcohol, benign prostate hyperplasia, and frequency of sexual activity and ejaculation. There is significant evidence showing that there is no association between these factors and prostate cancer.
There is convincing evidence that a family history of the disease increases your risk for prostate cancer.
The risk of developing prostate cancer is higher if a first-degree relative (your father, brother or son) has been diagnosed with the disease. The more first-degree relatives with prostate cancer a man has, the greater his risk of developing prostate cancer.
Risk is also influenced by your relative’s age at diagnosis. If your relative was diagnosed with prostate cancer before the age of 65, your chance of developing prostate cancer is higher than if your relative was diagnosed at an older age.
Possible risk factors
The following factors have been linked with prostate cancer, but there is not enough evidence to show they are known risk factors. Further study is needed to clarify the role of these factors for prostate cancer.
A diet high in fat, especially animal fat, may increase the risk of prostate cancer. Animal fat is found in milk and other dairy products. Some studies suggest that men who eat larger amounts of dairy products may have a higher risk for prostate cancer. Milk products also have calcium. Some studies suggest that a high calcium intake may increase the risk of developing prostate cancer.
Some studies show that eating a lot of red meat like beef or pork, especially when it is cooked at a high temperature, may increase the risk of developing prostate cancer. Eating a lot of processed meat like bacon or hot dogs may also put you at higher risk. Eating white meat doesn’t increase your risk for prostate cancer.
Inherited gene mutations
Studies show that some inherited gene mutations may increase the chance of developing prostate cancer. But only a very small number of cases of prostate cancer are linked with these gene mutations.
Men who inherit mutations of the BRCA2 gene may have a higher risk of developing prostate cancer. This gene mutation also increases 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 is called prostatitis. Many studies show that long-term inflammation of the prostate increases the risk of developing prostate cancer. It also makes prostate cancer grow and spread more quickly.
Androgens are a type of male hormone. They are responsible for the growth, development and function of the male reproductive system, including the prostate. Testosterone is the main male hormone. When the body uses, or metabolizes, testosterone, it creates dihydrotestosterone (DHT).
Some evidence suggests that androgens are related to the growth and development of prostate cancer. Long-term exposure to higher levels of testosterone and DHT may increase the chance of developing prostate cancer. Hormonal therapy that blocks the body’s production of these hormones is one of the treatments for prostate cancer.
Studies show that developmental factors that influence growth in the womb, during childhood and in adolescence are linked to a higher risk of prostate cancer. The findings show the taller a man is, the greater his risk of prostate cancer.
Studies suggest that farmers and workers who spray pesticides on crops have a slightly higher risk of developing prostate cancer. The risk may be even higher for men with a family history of prostate cancer.
Researchers don’t know which specific chemicals may be responsible for this increased risk. Pesticides have a large number of different chemicals, but only some of them may be related to prostate cancer.
Some evidence suggests that occupational exposure to the following chemicals may increase the risk for prostate cancer.
Cadmium is a metallic element known to cause cancer. Some studies show that men exposed to cadmium in smelting or battery manufacturing industries have a higher risk of developing prostate cancer. Further research is needed to determine how cadmium exposure affects prostate cancer risk.
Chemicals in rubber manufacturing may increase the risk for prostate cancer. There is some evidence that workers in the rubber manufacturing industry have a higher risk of developing the disease.
Unknown risk factors
It isn’t known whether or not the following factors are linked with prostate cancer. It may be that researchers can’t show a definite link or that studies have had different results. Further study is needed to see if the following are risk factors for prostate cancer:
- testosterone therapy
- sexually transmitted infections (STIs)
- lack of physical activity
- sedentary behaviour
- low levels of some dietary nutrients, including vitamin D, vitamin E and selenium
Questions to ask your healthcare team
To make the decisions that are right for you, ask your healthcare team questions about risks.
Cancer affects all Canadians
Nearly 1 in 2 Canadians is expected to be diagnosed with cancer in their lifetime.