Family history and cancer
It is not uncommon for more than one member of a family to have cancer
It is not uncommon for more than one member of a family to have cancer.
Trying to find information about cancers in your family and how to deal with them can be difficult. The following pages provide simple information about what it means to have a family history of cancer, some different types of family cancers and who you can contact for further information.
The information contained in this section should not be used for individual medical advice. Please see your doctor if you have concerns or specific questions relating to your health.
Family history
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 the same environmental and lifestyle risk factors, for example too much sun or smoking, or
- because there is an inherited faulty gene which increases the 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.
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:
Number of blood relatives* who have had cancer
The more blood relatives* who have had cancer (in particular breast, ovarian and/or bowel cancer), the more likely the cancer is due to an inherited faulty gene.
Ages at which cancers in the family developed
The younger people were when they developed cancer (compared to what is expected in the general community), the more likely it is to be due to inherited factors.
Pattern of cancer in the family
The type of cancer and who it affects in the family are important. In some families there are a number of blood relatives* who develop the same type of cancer, such as breast or bowel cancer. In other families there are some cancers that may run in the family (e.g. breast, ovarian or bowel cancer and cancer of the uterus). This happens because some faulty genes can cause more than one type of cancer.
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. It is important to know that some people who inherit a faulty gene which causes an increased risk of cancer never go on to develop cancer.
*A blood relative is someone related by blood (e.g. grandmother, father, sister), not marriage.
Family counselling and genetic counselling services
Genetic counselling services give people information about their chance of developing cancer based on their family history.
These services discuss ways that may help reduce the chance of cancer developing and methods of picking it up early. Sometimes genetic testing is possible, however it is only offered after the advantages and disadvantages of testing for the person and their family are discussed. Genetic testing is only useful if one of the family members with the cancer has been tested.
For more information about family cancer and genetic counselling services contact your doctor or Cancer Council 13 11 20.
Genetic testing
Genetic testing is the scientific testing of a person's genes and is usually done when someone is at an increased risk of having inherited a changed gene (mutation). Your eligibility for genetic testing will be based on family history and other factors such as a family member having a specific type of cancer and an altered gene is the cause.
For certain cancers, where there is a family history, it is possible to test from mutations in specific genes. For example, two genes called BRCA1 and BRCA2 are now known to be important in the development of hereditary breast and ovarian cancer.
Most cancer occurs in people with no family history so talk to your GP about genetic testing, if you are eligible, and if it's right for you.
Types of family cancer
A small number of families have an increased risk of certain cancers due to a change in their genes or inherited disorders. There are several types of family cancer outlined in the information below.
Familial adenomatous polyposis (FAP)
Familial adenomatous polyposis (FAP) is a rare inherited condition. Less than 1% of all bowel cancers in the general population are due to FAP.
People with FAP usually develop multiple (hundreds to thousands) small growths, called polyps, in the colon. The polyps are adenomatous, which means they are immediate precursors to colon cancer. These generally appear in the teenage years and, if left untreated, inevitably progress to bowel cancer.
For those who have inherited the gene change, regular bowel surveillance is extremely important. Screening, generally by colonoscopy, should start between the age of 10 to 15 years.
Hereditary non-polyposis colorectal cancer (HNPCC)
Hereditary non-polyposis colorectal cancer (known as HNPCC) is a rare inherited bowel cancer syndrome. Less than 5% of all bowel cancer cases are HNPCC.
People with HNPCC often develop large bowel cancer before the age of 50. They commonly have one or more adenomas (small polyps) in the bowel.
People not only have an increased chance of developing bowel cancer, but also cancer of the uterus and other types of cancer including ovary, kidney, ureter (tube that leads from the kidney to the bladder) small bowel, stomach and pancreas.
Hereditary breast and ovarian cancer (BRCA1 and BRCA2)
About 5% of breast and ovarian cancers are due to an inherited faulty gene. Two genes involved in hereditary breast and ovarian cancer are often referred to as BRCA1 or BRCA2.
Their names come from the abbreviation of the genes 'Breast Cancer One' and 'Breast Cancer Two'.
Neurofibromatosis 2 (NF2)
Neurofibromatosis 2 (NF2) is a rare inherited disorder which causes tumours to grow on various types of nerves and which can also affect the development of non-nervous tissues such as the bone or the skin. Signs of NF2 usually appear when people are in their 20s, however may occur earlier or later in life.
Von Hippel Lindau syndrome (VHL)
Von Hippel Lindau syndrome (VHL) is a rare inherited disease that can present in many different ways in family members. Very small blood vessels, or capillaries, knot together to form abnormal growths called angiomas. These angiomas may cause little or no problem in some family members, whereas others may have very serious health problems.
Retinoblastoma
Retinoblastoma is a very rare tumour of the immature cells of the retina in one or both eyes. This only occurs in babies or toddlers under the age of five. Some children have an inherited form of retinoblastoma.
Melanoma
Less than 5% of all melanoma cases are due to an inherited faulty gene. It may occur in families where there are multiple cases of melanoma on the same side of the family and the presence of atypical or unusual moles, where melanoma occurs at an early age, and sometimes if ocular (eye) melanoma and pancreatic cancer is in the family.
For further information click here.
Multiple endocrine neoplasia type 1 (MEN1)
Multiple endocrine neoplasia type 1 (MEN1) is a rare inherited condition. People with MEN1 frequently develop peptic ulcer disease and abnormalities in the endocrine glands: the pituitary, parathyroid and pancreas. Symptoms vary greatly. Sometimes cancers develop in these glands.
Multiple endocrine neoplasia type 2 (MEN2)
Multiple endocrine neoplasia type 2 (MEN2) is a rare inherited condition where cancers develop in one or more endocrine glands, the thyroid, the adrenal and the parathyroid glands. People with MEN2 may have an increased level of hormones which result in a range of mild to severe side effects. It affects both males and females.
Family cancer clinics in Australia
What do family cancer clinics provide?
Family cancer clinics provide counselling and information for families with a history of cancer on:
- inheriting cancer
- individual risk
- screening
- cancer risk reduction strategies.
They also provide genetic testing where appropriate. The clinics are conducted through the public hospital system and there is no direct cost to the patient for consultation or genetic testing.
Who attends a family cancer clinic?
Types of families often referred to a clinic are:
- families with three or more individuals with a specific type of cancer – often breast, ovarian or bowel cancer.
- individuals with multiple cancers diagnosed at an unusually young age.
How can you attend a family cancer clinic?
Clinics differ from state to state. To attend a clinic, ask your GP, physician or surgeon to refer you to one most convenient for you. In some states you can telephone direct to refer yourself (self refer).
When you attend a clinic you may see a genetic counsellor, medical geneticist and other medical specialists depending on the type of cancer.
Where are the clinics located?
genetics.edu.au
Find out more information about causes and prevention of cancer