Hereditary ovarian cancer risk
Understand your genetic risk
This guide is for anyone who wants to know more about genetic risk factors for ovarian cancer. This includes people diagnosed, and people with ovarian cancer in their family.
Knowing your risk can help you and your family make better decisions about your health.
What is hereditary ovarian cancer?
At least one in ten people diagnosed with ovarian cancer have an inherited genetic risk that increases the chance of getting ovarian cancer. This is called hereditary ovarian cancer. Other family members may also carry this genetic change and both women and men can pass this genetic risk onto their children.
Every woman, and person born with ovaries and fallopian tubes, has some risk of ovarian cancer. For the average person, this is 1.6%, i.e. one to two out of one hundred people will get ovarian cancer in their lifetime. But, this risk is higher for people with certain genetic changes (mutations).
Many genetic mutations are harmless. But, some are pathogenic. This means they raise the risk of cancer or other diseases. Sometimes pathogenic mutations are inherited. They can also happen because of our lifestyle, the environment, and by chance.
If you inherit a genetic mutation, it is in every cell of your body. You can pass it onto children who get a copy of their genes from each parent. Usually the chance of an inheritable ovarian cancer genetic risk passing from parent to child is 50/50. If genetic changes happen later in life, they are only in specific cells and can’t be passed onto children.
Not everyone with a hereditary risk of cancer gets cancer. It’s a bit like a really bad luck lotto ticket. If you inherit a harmful change, you have some of the lotto numbers. But further genetic changes are needed for all of your numbers to come up. For ovarian cancer, the main decider is usually chance. Even so, there may be things you can do to reduce your risk.
Causes of hereditary ovarian cancer
Mutations in the BRCA1 or BRCA2 Genes
This is the most common hereditary ovarian cancer condition. BRCA stands for BReast CAncer gene. The BRCA gene’s job is to help fix damage to our DNA and control cell growth. Harmful changes in the BRCA1 and BRCA2 genes raise the risk of breast and ovarian cancer. They also raise the risk of prostate and pancreatic cancer, though less so.
- BRCA1 is associated with an average risk of 44% for ovarian cancer. This means that for every 100 people with a harmful BRCA1 mutation, approximately 44 will get ovarian cancer in their lifetime.
- BRCA2 is associated with an average risk of 17% for ovarian cancer. This means that for every 100 people with a harmful BRCA1 mutation, approximately 17 will get ovarian cancer in their lifetime.
- BRCA mutations are associated with a 61-79% risk of breast cancer in women. This means that out of every 100 people with a harmful BRCA mutation, 61 to 79 will get breast cancer in their lifetime.
BRCA mutations are linked to epithelial ovarian cancer. About 20% of people diagnosed with high-grade serous, up to 4% with low-grade serous and 2% with clear cell ovarian cancer have a BRCA mutation.
Lynch Syndrome
Lynch Syndrome is another genetic condition that can raise the risk of ovarian cancer. It is caused by a pathogenic change in one of 5 genes known as the mismatch repair genes (MLH1, MSH2, MSH6, PMS2r EPCAM). Normally these genes help fix damaged DNA. A gene mutation affects the normal DNA repair mechanism, which increases cancer risk. Lynch Syndrome also increases the risk of other cancers – predominantly colorectal and endometrial cancer. Other cancers linked to Lynch Syndrome include small intestine, stomach, urothelial, bile duct and brain cancer but the risks are lower for these cancer types compared to colorectal cancer. The risk of specific cancers varies depending on the gene that is altered.
The following statistics are for women up to age 70.
- MSH2/EPCAM is associated with a 17% risk of ovarian cancer. This means that out of 100 people with a harmful MSH2/EPCAM mutation, 17 will get ovarian cancer in their lifetime.
- MLH1 and MSH6 are each associated with a 11% risk of ovarian cancer. This means 11 out of 100 people with a harmful MLH1 or MSH6 mutation will get ovarian cancer in their lifetime.
- PMS2 is associated with a near normal risk of ovarian cancer.
- The risk of bowel cancer ranges between 12 and 53% depending on the affected gene, and there are gender differences for bowel cancer risk.
- The risk of endometrial cancer ranges between 15-47% depending on the affected gene.
The types of ovarian cancer associated with Lynch Syndrome are endometrioid and clear cell ovarian cancer.
Find more information about Lynch Syndrome from the New Zealand Familial Gastrointestinal Cancer Service.
Mutations in other genes
Other genetic causes of ovarian cancer are more rare. They include changes to the genes ATM, BRIP1, PALB2, RAD51C, and RAD51D. Depending on the gene affected the risk of ovarian cancer ranges from 3.6 to 23%.
Who is most at risk?
You are more likely to have a hereditary ovarian cancer condition if:
- A blood relative has been told they have a cancer gene mutation.
- Multiple relatives on the same side of the family have been diagnosed with the same cancer or related cancers. For example, ovarian and breast cancer could suggest BRCA; colorectal, endometrial, and ovarian cancer could suggest Lynch Syndrome.
- You or other people in your family were diagnosed with cancer at a young age.
- There are rare cancers in your family (such as male breast cancer).
- You have Jewish ancestry.
- You have high-grade epithelial ovarian cancer.
If you want to learn more about your risk, talk to your general practitioner or cancer specialist.
Preparing for your appointment
Your doctor will want to know about any people in your family who have had cancer including you. They are interested in people who are related by blood (not marriage) on both your mother and father’s side.
This could include:
- Your mother’s parents (maternal grandparents)
- Your father’s parents (paternal grandparents)
- Your parents
- Any siblings you have
- Any children you have
- Other relatives like your great-grandparents, great-aunts and uncles, cousins, nieces and nephews
The more you can learn about:
- Who had cancer and their relationship to you (e.g. your half-sister, or grandfather)
- What type of cancer they had
- How old they were when they got cancer
- How they found out they had cancer
The more accurately your chance of a hereditary cancer condition can be determined.
Genetic testing eligibility
Genetic Health Service NZ is the free genetic counselling and testing service provided through Health New Zealand | Te Whatu Ora.
Genetic testing is publicly funded when someone has a ten percent or higher chance of having a hereditary condition. This is based on your personal and family history of cancer.
If you have high-grade serous ovarian cancer, you will be offered urgent testing because the genetic testing results can influence treatment decisions.
You can also pay for genetic testing through a private service. A New Zealand registered genetic counsellor can interpret your results in the context of your family history and the New Zealand Health system.
A list of private providers can be found on the Human Genetic Society of Australasia website.
Seeing a genetic counsellor
Genetic counsellors are health professionals with specialist knowledge in human genetics. They understand the challenges faced by people and families who have, or may have, an inherited condition.
You usually have two appointments. The first is to learn more about you and arrange testing if needed. The second is to discuss any test results and arrange any follow up.
If you have high-grade serous ovarian cancer, your oncologist might offer to test you for BRCA mutations directly and refer you to a genetic counsellor if the test is positive.
Your genetic counsellor can:
- Review your family history and assess your chance of having a familial cancer syndrome.
- Provide information about these conditions, their management and inheritance.
- Discuss what types of genetic testing may (or may not) be indicated.
- Discuss the benefits and risks of genetic testing and support your decision making.
- Address any concerns that you or your family may have about living with or testing for an inherited condition.They can link you into support groups and reliable information sources.
- Give information and surveillance recommendations for you and (where indicated) for close family members.
- Arrange referrals for management and surveillance for cancer risk and for follow up of any issues that arise from the appointment.
You should leave the appointment understanding:
- What genetic testing (if any) has been arranged.
- The possible outcomes of testing and how the results will be managed.
- The answers to any particular questions or concerns you have.
Considerations before getting genetic testing
The genetic counsellor will help you understand the benefits and risks of genetic testing so you can decide if it’s right for you. Some things they may raise with you include:
- If genetic testing finds a hereditary cancer risk, your family can also get tested.
- There may be actions you and your family can take to reduce your risk of ovarian and other cancers.
- The information may be useful for family planning.
- If you have ovarian cancer, the result may help your doctors understand which treatment is best for you.
- It’s a good idea to talk to family before deciding to have a genetic test. The information will have implications for them too.
- Insurance companies may use the results to deny coverage or raise premiums. For example, you may not be able to get health or life insurance, or if you have a policy you may have to pay more. This could affect both you and family members.
- The result could have an impact on you and your family’s emotional wellbeing.
Getting a genetic test
Genetic testing usually involves a blood test. Your genetic counsellor will give you a form for this. It can take up to three months to get the results, but if it’s urgent you will get the results sooner. If you have high-grade serous ovarian cancer, you should get the results before you finish chemotherapy.
You’ll have another appointment to talk about the results and what they mean. If you have a higher cancer risk, you’ll get more information about what you and your family can do to manage it. You might also be referred to other services to help plan how to manage and prevent certain cancers.
Possible results
There are three possibilities from testing:
- Negative test. No genetic changes/mutations are detected. This means it is very unlikely you or your children have a hereditary cancer syndrome. Other family members may still have some risk depending on their personal and family history.
- Positive test. A pathogenic gene change was found that could increase your risk of ovarian and other cancers. The medical name is an inherited cancer susceptibility condition. Some family members may have this change too. Your genetic counsellor will help you understand what this means. See ‘when the test is positive’ for more information.
- Uncertain significance. All genes have some changes (variants) but not all changes cause problems. Sometimes geneticists do not know enough about a specific change to say whether the change is harmless or not. This is called a variant of uncertain significance (VUS). More information may become available in the future. You should be reviewed in three to five years. More information: Variant of Uncertain Significance – Center for Genetics Education
Because more than one gene is tested at a time, you may have a positive result and a variant of unknown significance.
Your genetic counsellor will talk through what the result means for you and your family.
If the test is positive there may be things you can do to find cancer early, or prevent it. You will be referred to specialist services for surveillance and management.
If you have been diagnosed with high-grade serous ovarian cancer, your doctor may talk to you about a type of treatment called olaparib.
Ovarian cancer prevention and risk reduction
If you haven’t been diagnosed with ovarian cancer, risk-reducing surgery is the most effective option to prevent or reduce the risk of ovarian cancer in women and people born with fallopian tubes and ovaries.
Prophylactic surgery to remove the ovaries and fallopian tubes
The best way to reduce ovarian cancer risk is to have your ovaries and fallopian tubes removed (risk reducing surgery). The medical name for the surgical procedure is bilateral salpino-oophorectomy. A gynaecologist or gynae-oncologist would normally perform the surgery.
If you are at high risk of ovarian cancer, this can reduce your risk to near normal levels. In other words, for most people this surgery will stop them getting ovarian cancer. Like all surgeries, removing the ovaries and fallopian tubes has some risks that the surgeon will explain.
If someone is still having their periods, removing the ovaries will cause menopause and infertility. Surgical menopause has worse symptoms than natural menopause. It can raise the risk of health problems, such as heart disease and osteoporosis. For this reason, surgery is not usually done before the age of 40 years of age. Hormone replacement therapy (HRT) after surgery may help symptoms and lower health risks.
More information:
Surgical Menopause – Australian Menopause Society
How Can I Reduce My Inherited Cancer Risk – Inherited Cancers Australia
Oral contraceptive pill
Although there is evidence the combined oral contraceptive pill can reduce ovarian cancer risk, it is significantly less effective than surgery to remove the ovaries and fallopian tubes and it is not recommended for cancer prevention.
Experimental strategies being researched
Fallopian tube removal
Most ovarian cancer starts in the fallopian tubes. Researchers are investigating whether removing the fallopian tubes only could be a better option. They are also looking at what happens if the fallopian tubes are removed at a younger age, before removing the ovaries later.
Removing the fallopian tubes has less side effects than removing the ovaries because it doesn’t cause menopause. However, natural pregnancy is not possible after this procedure.
But there is not enough evidence for these strategies yet.
More information:
Salpinectomy for Ovarian Cancer Prevention – Society of Gynecologic Oncology
Screening
Surveillance screening is not currently recommended in New Zealand as it has not been proven to reduce deaths from ovarian cancer in contrast to risk-reducing surgery to remove the fallopian tubes and ovaries.
The Familial Ovarian Cancer Screening Study (FOCSS) was a UK study. It investigated if screening could find ovarian cancer earlier in people at increased risk. People in the study had a special type of CA-125 blood test called ROCA every four months. They also had a yearly ultrasound. The study found more early ovarian cancer but, over half of people who got ovarian cancer were still diagnosed with advanced cancer.
NICE in the United Kingdom recently updated their guidelines to allow for four monthly surveillance screening with ROCA, when people at risk choose to delay or not-have risk-reducing surgery.
It is important to note that surveillance is not an alternative to risk-reducing surgery. Surveillance does not reduce the risk of developing ovarian cancer, and it is not known whether it can improve outcomes or save lives. If you have questions you should talk to your doctor.
More information:
Eve Ovarian Cancer UK – ‘Survaillance to be offered to those at highest risk of ovarian cancer for the first time on the NHS’
Reducing the risk of other cancers
Breast cancer (with the BRCA gene)
If you have not had breast cancer, depending on your risk level prevention and risk reducing options may include:
- Prophylactic surgery to remove the breasts (bilateral mastectomy), with reconstruction afterwards
- Surveillance with mammograms and MRIs
- Estrogen blocking medication (usually tamoxifen or anastrozole)
More information:
Risk reducing options – Breast Cancer Foundation NZ
How Can I Reduce My Inherited Cancer Risk – Inherited Cancers Australia
Bowel cancer (with Lynch Syndrome)
People with Lynch Syndrome should get an annual colonoscopy. It helps find bowel cancer earlier. Depending on the specific gene affected, this starts when you turn 25, or 35.
More information:
Lynch Syndrome – New Zealand Familial Gastointestinal Cancer Service
Ovarian cancer treatment
If you have a BRCA mutation and have been diagnosed with high-grade ovarian cancer you may benefit from PARP inhibitor treatment. PARP inhibitors stop cancer cells from repairing themselves.
A specific PARP inhibitor called olaparib is funded by Pharmac for BRCA mutations in high-grade serous. Olaparib is a pill you take every day, usually starting within 12 weeks of finishing chemotherapy. Alternative PARP inhibitor treatment is available for people with high-grade serous who do not have the BRCA 1/2 mutation. Your oncologist will give you more information.
Sharing your results with family
Your genetic test results can help your family understand more about their risks.
If your test is positive it is especially important to let family members know. There is an increased chance that they may also have the condition. If they want, they can get genetic testing to find out. This is called predictive testing.
If your test is negative your children are unlikely to have any risk. But, other family members may still have some risk depending on their history.
For considerations around sharing your results with family members and children see:
Genetic Testing and Family Relationships – Breastcancer.org
Inherited Cancers Resource Center/Family – Inherited Cancers Australia
Thank you to Alice Christian from Capital Genetics for supporting the development of this guide.
Last reviewed: 18 May 2026