How to explore your family history of cancer

It's Hereditary Cancer Awareness Week - a time to shine a light on the genetic faults (or mutations) that can run in families and raise a person’s risk of cancer. 

Multiple cases of certain cancers in your family could be a sign that you are at risk. However, it can be difficult to piece together your family’s medical history, and understand what it means for you. That's why we asked Genetic Counsellor Beth Coad to give us her expert tips on exploring your family history - from how to start conversations with family members around cancer, to the signs that mean you could be eligible for genetic testing. 

Your genetic risk 

Every person has some risk of developing cancer. This risk may be higher or lower due to a mix of genetic, hormonal, and environmental factors. Family history can also increase your risk of cancer. The topic of cancer can be difficult to discuss and may be upsetting to some people. So how can you learn more about your own family history of cancer and learn more about how that history could affect you?

Starting the conversation 

Families are diverse and may have different communication preferences, but genetic counsellors like myself hear stories from patients about what has been helpful to them in starting the conversation about a family history of cancer. Many find TV or other media about cancer can be a good starting point. For example, ask your relatives if they have seen the section on morning TV about breast awareness, or maybe bring up that cancer charity bake sale in your workplace.

It’s also important to know your audience and the settings to have these conversations in. Some families find themselves reminiscing around the holidays or at the dinner table. Family gatherings may be a good opportunity to ask questions about extended relatives. For others, one to one settings like a car ride or a walk can be a good time to discuss topics like this.

Exploring both sides of your family  

Cancer risk can be affected by family history or specific cancer risk genes that can be passed down, or inherited, in the family.  There is a common myth that inherited causes of cancer are passed down the ‘female line’ but inherited cancer syndromes can have implications for everyone in a family. It’s best to record all cancers at least back to your grandparents, or even their siblings if you can.

What to look out for in your family history

We know that cancer sadly affects 1 in 2 people in their lifetime. Many of these people will have no family history of cancer. However, some of them will develop cancer due to high risk inherited causes (such as BRCA1 or BRCA2 gene changes). There are some clues that suggest a possible inherited cause:

• People being affected at a young age – for example, ovarian cancer is less commonly seen below the age of 60
• The type of cancer – for example, the types of ovarian cancer classed as epithelial (serous/endometrioid/clear cell) or Sertoli-Leydig can be linked to an inherited cause
• Other types of cancer, like lung and cervical, are less likely to have an inherited cause
• Two or more people on one side of the family affected with the same cancer
• A pattern of cancers in a family – for example breast and ovarian cancer can suggest a BRCA1/BRCA2 genetic change or relatives affected with bowel, womb and ovarian cancer may suggest Lynch Syndrome
• One person affected by two or more new cancers

What information is needed for a genetics assessment?

To give the most accurate advice about cancer risk, we may need to confirm the types of cancer seen in the family. For example, gynaecological and other abdominal cancers commonly get mixed up as stories pass through families. So, any documents you have, such as doctor’s letters, or death certificates, can be helpful. If you don’t have these documents, try to find as many details as you can such as full names, date of birth, date of death and any hospitals relatives were treated at.

What to do if you are concerned about the family history of cancer

The first place to go is your GP as they can refer you for an assessment of your family history locally. Alternatively, if you have been diagnosed with cancer yourself your treatment team should also be able to make a referral.

Beth Coad is a Genetic Counsellor at St George’s University Hospitals NHS Foundation Trust and has a specialist interest in Cancer and General Genetics.