Familial ovarian cancer
The two genes involved in familial breast cancer (BRCA1 and 2) are also involved in familial ovarian cancer and many families are looking for information on the possibility of genetic testing for ovarian cancer.
This factsheet summarises the present knowledge on genetic testing for ovarian and breast cancer, and looks at screening currently available for ovarian cancer when two or more relatives have developed ovarian or breast cancer.
Can anyone have a genetic test to tell if they will develop ovarian cancer?
Most cancer genetic cancer centres offer testing to families with at least three people affected with ovarian or breast cancer.
The two genes involved in ovarian and breast cancer, called BRCA1 and BRCA2, are long genes and a fault in one of these genes can occur anywhere along the line-up of the gene. Different families have different faults. In order to detect a faulty gene we therefore have to take a blood
sample from someone with ovarian or breast cancer in the family and work our way along the gene until we have identified the fault responsible in that particular family. Once we have found the fault in someone with ovarian or breast cancer in the family we are then able to offer genetic testing to other people in that family to tell if they have inherited the faulty gene.
Genetic testing is a two stage process. The first stage is to identify the faulty gene in the family, and the second stage is then to test other members of that family, if they wish to determine if they have the faulty gene. Because detecting a faulty gene is a difficult and time consuming process most centres offer to search for a faulty gene in families where it is probable that a faulty
gene is present, ie families with three or more people with ovarian or breast cancer, with one person in the family, with ovarian or breast cancer willing to give a blood sample to allow us to start the faulty gene search.
If a faulty gene is found in my family, do I have to have a genetic test?
Once a faulty gene has been identified in your family you will be offered a genetic test, but you do not have to take up the offer. It is entirely up to you, and you will have to decide if you want a test. There will be no pressure on you at all.
If a faulty gene is found and then my test shows I have that faulty gene, what are the options available to me?
If you have the faulty gene then you have two possible options available at the moment:
- Screening - having regular screening tests (ultrasound and CA125 measurements done annually) to try and detect ovarian cancer early.
- Surgery - removing the ovaries to try and prevent ovarian cancer developing.
If you have a faulty BRCA1 or BRCA2 gene you are also at increased risk of breast cancer, and again the options are similar:
- Screening - regularly mammography to try and pick up early breast cancer, or
- Surgery – a bilateral mastectomy to remove the breast tissue thus trying to prevent the development of breast cancer.
It is very likely that a third option of taking different drugs in research studies to try and prevent the development of these cancers will become available soon. One study, the International Breast Cancer Intervention Study (IBIS) offers a trial of Tamoxifen or a dummy tablet to those with a family history of breast cancer. There are no drug studies available for women with a family history of ovarian cancer, or for women who have had a genetic test which
proves they carry the faulty BRCA1 or BRCA2 genes.
If a faulty gene is found, and my genetic test shows that I do not have that faulty gene, what happens then?
If you do not have the faulty gene which runs in your family, then your chance of developing ovarian or breast cancer is no higher than anyone else your age in the population, and therefore extra screening will be stopped. You will still be encouraged to join the National Breast Screening
Programme when you are 50.
If my mother and my aunt both developed ovarian cancer, will I never be offered gene testing?
As techniques for identifying faulty genes improve, it is very likely that many more people will be offered testing.
Where do I get more information on genetic testing?
Information on genetic testing is available from CancerBACUP, the Cancer Research UK.
My mother has ovarian cancer, and no-one else in the family has ovarian or breast cancer. Should I be screened?
If your mother is the only person in the close family with ovarian or breast cancer, then your risk of developing ovarian cancer is only slightly increased.
Who can get screening because of their family history?
The UKCCCR National Familial Ovarian Screening Study offers screening with annual ultrasound and annual CA125 measurement to women between the ages of 25 and 65, who come from an “at risk” family. An “at risk” family is defined as:
- Two first degree relatives with ovarian cancer.
- One first degree relative with ovarian cancer and one first degree relative with breast cancer, diagnosed under the age of 50.
- One first degree relative with ovarian cancer and two first or second degree relatives with breast cancer, diagnosed under the age of 60.
- The presence of a faulty ovarian cancer causing gene in the family.
- Three first or second degree relatives with bowel cancer and one case of ovarian cancer in the family.
A first degree female relative is mother, daughter or sister.
A second degree female relative is grandmother, granddaughter, aunt or niece.
You will be offered screening in this study if you come from an “at risk” family and you have a first degree relative who has breast or ovarian cancer. If you think you are eligible for this study ask your general practitioner to refer you to your nearest participating centre.
