Learning hubProstate cancer

Family history and prostate cancer risk

August 16, 2021

Family history and prostate cancer risk

Many diseases and condition are know to run in families. Sometimes this is because many families have similar lifestyles, other times it is due to genetics. There has been a lot of research into how much of an effect family history has on prostate cancer. This article aims to summarise some of the major studies in this area.

Family history is only one of several risk factors for prostate cancer, you can find information on other risk factors here.

Which family members are important in a family history?

Generally speaking any biological relative can be important to consider when understanding your family history. When talking about prostate cancer most research tends to look at relatives with prostate or breast cancer. We say biological to cover only those that you may share some genes with. If you were adopted for example, your adoptive parents would not be considered when discussing family history.

Studies typically look at first and second degree relatives. A first degree relative is someone in your direct family. Your parents and siblings are all considered first degree relatives. A second degree relative is anyone who is a first degree relative of your parents. This includes uncles and aunts as well as both sets of grandparents.

While we all do technically have relatives beyond this, links to them tend to be less well studied.

What do I need to know about my first and second degree family members to help assess my prostate cancer risk?

The first question to ask each of your first and second degree relatives is if they have ever been diagnosed with prostate or breast cancer. If any of your family members passed away and you are unsure if they had been diagnosed they would be considered a ‘no’ in most of the academic research. It is possible they were or would have been diagnosed in the future. Because many studies are based only on known diagnosis we can’t dig any deeper into their history. More specific markers in the human genome are an active area of research and may one day give us a definitive guide.

The second fact you need to know is when they were diagnosed. There have been shown to be differences in your risk depending on the age at diagnosis of your first degree relatives.

How does family history change my risk?

One first degree relative with prostate cancer

If your single first degree relative was diagnosed over the age of 55, studies suggest your risk is between 1.6x and 1.8x that of a man with no family history.

On the other hand, if your brother or dad was diagnosed younger than 55, that risk jumps to 2.5x that of a man with no family history.

These increases in risk are significant and should not be ignored. If you know you have a family history or later discover you do most doctors recommend you discuss testing. You can do that with one of our dedicated prostate testing doctors by Becoming a Member.

More than one first degree relatives with prostate cancer

If both your first degree relatives were diagnosed when they were older than 55, you have a 3.5x risk of prostate cancer compared to a man with no family history.

If they were diagnosed younger than 55 that risk jumps to 6x the normal level.

With a strong family history many guidelines and studies recommend considering prostate cancer testing as young as 40. There is evidence that men with a family history of younger prostate cancer may themselves be at risk at an earlier age.

Second degree relatives and relatives with breast cancer

hile not as strong as first degree relatives there is evidence that risk of prostate cancer increases with both second degree relatives and both first and second degree relatives with breast cancer.

This risk has been shown to be around 1.5x the risk of a man with no family history.

The links between prostate and breast cancer patients is still under active research. Some breast cancers result from the BRCA1 or BRC2 gene which has been shown to increase a man’s risk. The recent MRI Rebate for prostate cancer includes provisions for men with a suspected BRCA gene as well as other family history of prostate cancer.