Most ovarian cancers are not caused by inherited genes, and most women who get ovarian cancer don’t have a family history of it.
If you have just one female relative who has been diagnosed with ovarian cancer, your risk is unlikely to be very different from other women the same age as you.
But sometimes ovarian cancer can run in families. In general, the chance of there being a family link is greater when:
- a number of family members have been diagnosed with ovarian cancer, or related cancers such as breast cancer
- the family members are closely related
- the family members were diagnosed at a younger age.
Inherited genes and ovarian cancer
Around 5 to 15 of every 100 ovarian cancers are thought to be due to a change (alteration) in a gene running in the family. The two genes that are most often found to be altered in hereditary ovarian cancer are called BRCA1 and BRCA2.
If a family has an altered BRCA1 or BRCA2 gene, usually several relatives on the same side of the family are diagnosed with ovarian cancer or related cancers. People in the family may also be diagnosed with cancers at a particularly young age.
BRCA gene alterations are more common in certain populations. If you have Ashkenazi Jewish ancestry and have relatives with ovarian or breast cancer, you may want to discuss your risk with your GP.
If you are concerned about your risk of ovarian cancer, talk to your GP. They can talk to you about your family history and your risk.
Assessing family history
A family history of cancer is usually based on your first-degree relatives and close relatives.
First-degree relatives are your parents, brothers, sisters and children.
Close relatives are your first-degree relatives and second-degree relatives (grandparents, grandchildren, aunts, uncles, nieces and nephews).
If any of the following are present on one side of your family, it’s possible that there may be an inherited altered gene that increases the risk of ovarian cancer:
- two or more close relatives diagnosed with ovarian cancer, including at least one first-degree relative
- a first-degree relative diagnosed with ovarian cancer and a close relative under the age of 50 diagnosed with breast cancer
- a first-degree relative diagnosed with ovarian cancer and a male relative diagnosed with breast cancer
- a first-degree relative diagnosed with both ovarian cancer and breast cancer
- a first-degree relative with ovarian cancer, and two close relatives diagnosed with breast cancer before they reached an average age of 60
- one close relative with ovarian cancer, and three or more relatives with bowel or womb (endometrial) cancer, or both.
If your GP agrees that you may be at increased risk because of your family history, they will refer you to a clinical genetics service or a family cancer clinic.