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Familial cancer

What is a family history of cancer?
 
Cancer is common - many people have someone in their family who currently has or has had cancer. It is not uncommon for more than one member of a family to have cancer.

Cancer can occur in families
  • just by chance, which is most often the case 
  • because family members have environmental and lifestyle influences in common, for example too much sun or smoking 
  • because there is an inherited faulty gene which leads to an increased risk of cancer, which is uncommon.
Only a small percentage of certain cancers (up to 5%) are due to a faulty gene inherited from either the father or mother. This is what we call a familial or family cancer. This can also be referred to as an inherited predisposition to cancer. The faulty gene increases the risk of cancer, but even then it does not mean every family member will develop the cancer.
 
 
Are some cancers more likely to be familial than others?
 
In general, the great majority of cancers are not familial.
  • some breast, ovarian, endometrial and bowel cancers can be due to an inherited mutation, but most are not
  • others such as lung cancer, leukemia and cervical cancer are rarely due to an inherited mutation
  • some rare cancers have a familial tendency.
There may be a familial basis for other cancers such as prostate cancer, melanoma and testicular cancer, but the particular genes responsible for this haven't been identified yet.
 

How can I tell if my family has a history of cancer?
 
Look at the family history on both your father’s and your mother’s side of the family. The clues that cancers in the family may be due to an inherited faulty gene include
  • the number of blood relatives (eg mother, grandmother, brother, sister - not related by marriage) who have had cancer
  • cancer developing at a younger age than is usual in the community 
  • pattern of cancer in the family. Families may develop the same cancer, or several cancers, depending on the which faulty gene is involved. 
The more clues that are present, the more likely it is that there is an inherited faulty gene in the family causing a higher than usual chance of cancer. However, it is not definite. Some people who inherit a faulty gene which causes an increased risk of cancer never go on to develop cancer.
 
 
Why is important to know about familial cancer?
 
Knowing you're at increased risk of developing cancer is useful because 
  • your risk of cancer may be able to be reduced 
  • any cancer can be diagnosed at an early stage, increasing the chance that it can be cured.
 
Where do I find out more about familial cancer?
  • talk to your doctor if you are concerned about cancer in your family
  • you can help by drawing a family health tree with all of your blood relatives on both sides of the family for three generations (if possible). As best you can, record any cancers for each person, the age at which they were diagnosed, and the age at death.
  • your GP can refer you (if there is a suggestion of a familial cancer) to the SA Familial Cancer Service for further assessment, advice, and (in some cases) genetic testing.
  • call the Cancer Council Helpline 13 11 20 to talk about your concerns.
Find out more
 
Familial cancer resources from Cancer Council South Australia
 
Useful websites*
South Australian Familial Cancer Service  - genetic counselling and testing service in South Australia
National Breast and Ovarian Cancer Centre (Australia) - information about breast cancer, ovarian cancer and family history and research
Centre for Genetics Education (Australia) - information for individuals and family members affected by genetic conditions, how to draw a family health tree, and a description of genes, mutations and inheritance
National Human Genome Research Institute (USA) - see particularly the glossary of genetic terms 
Human Genetics Advisory Committee (HGAC) - monitoring of genetic technology developments in Australia and the implications for people with risks/ family histories of inherited disorders like familial cancers.
* Please be aware that there are differences in the risks of cancer in different communities and countries, and that the risks of cancer reported on some international web sites may not necessarily apply in Australia.
 

GeneTrek 
 
A cancer genetics newsletter for clients of the SA Familial Cancer Service that provides up-to-date information for individuals with inherited cancers and cancer syndromes about cancer risk reduction, surgical and treatment options, research, genetic testing and counselling issues.
 
Latest edition
November 2009

Previous editions
 
May 2009 
April, November 2008
March, November 2007 
March, October  2006
March, September 2005 
March, October 2004 
November 2003 
 
 


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