The possible results of a genetic test
There are three possible results for testing for gene variants:
- 1. Variant present – sometimes called a positive test result.
Testing finds a variant that causes a significant change to the gene and is therefore very likely to be the cause of your cancer. You'll be told which gene the variant is in.
- 2. Variant not present – sometimes called a negative test result.
Testing hasn't found any gene variants.
- 3. Variant of unknown significance (VUS) – sometimes called an inconclusive test result.
Testing may find a variant in the gene where there may be some uncertainty whether or not this would cause an increased cancer risk. A VUS is a variant that's not currently known to cause an increased cancer risk. But a small number may get changed to a variant that causes a significant change to the gene and is cancer causing in future.
Our information focuses on information about BRCA1 and BRCA2 gene variants as they account for most hereditary ovarian cancers. For the most up-to-date information about genetic testing, please contact our support line.
Impact of ‘variant present’
If you've been told there’s a variant present you'll be told whether the variant is in your BRCA1 or BRCA2 gene or another gene.
The result will have an impact on your risk of developing other cancers, the risk of your family members developing cancer, and it may also have an impact on your treatment for ovarian cancer. You’ll receive counselling to explain the impact of this result.
You'll have the option of a follow up appointment with your local clinical genetics service to discuss how you're feeling and the impact the result can have on you and your family. They’ll be able to give you further information and tell you where you can access further support.
What's the impact on my treatment?
There's ongoing research into new treatment options for those with ovarian cancer who carry known variants in the BRCA1 or BRCA2 gene. Studies indicate that the prognosis (prediction of how your ovarian cancer might change in the future) for BRCA1 or BRCA2 carriers may be better than for those with no gene variants because carriers can have an increased response to specific treatments.
Targeted treatment (PARP inhibitor drugs)
If you have a BRCA gene variant found by either germline or somatic testing it may affect your treatment for ovarian cancer. PARP inhibitors are a group of drugs which work by stopping cancer cells from repairing damage in its DNA, with the aim that the cancer cells will die.
You can receive a PARP inhibitor if you have advanced ovarian cancer (stage 3 or 4) and have recently had and responded to platinum-based chemotherapy (usually carboplatin/cisplatin and paclitaxel). Which drug you’re offered will depend on which nation in the UK you live in, whether you have a BRCA variant, if your tumour tests positive for homologous recombination deficiency (HRD) and which medication your team think will suit you best.
More about targeted treatments you can access
Taking part in clinical trials about treatment
There's clinical trials on PARP inhibitors and other studies for those with a BRCA1 or BRCA2 variant or hereditary ovarian cancer. For more information talk to your medical team, explore our clinical trials information or contact our specialist nurse-led support line.
The risk of breast cancer
If you have ovarian cancer and a variant in the BRCA1 or BRCA2 gene, the risk of developing breast cancer is also increased. For a woman in the general population the lifetime risk of developing breast cancer is about 15 per cent (15 in 100 chance). If you have a BRCA1 or BRCA2 variant, the risk is around 65 to 80 per cent (up to 80 in 100 chance). Remember, an increased risk doesn’t mean you’ll definitely develop breast cancer.
How can I manage my increased risk of breast cancer?
A genetic counsellor will talk to you about the different ways of reducing your risk of developing breast cancer. There are three options to consider – screening, risk-reducing surgery and drug treatment. The choice will take into account your current health and whether the ovarian cancer could grow or change. You may also be referred to a family history breast cancer clinic where specialists in this area will take over your care.
The NHS runs a breast screening programme for women throughout the UK. Women between the ages of 50 and 70 are typically invited for breast screening every three years, but those at high risk can access screening tests before the age of 50 and any woman can request screening to continue after the age of 70.
If you have a BRCA1 or BRCA2 gene variant you’ll be considered for yearly MRI scans and mammograms from the age of 30–40 onwards. A mammogram is a type of x-ray. Ask your genetic counsellor for further information.
Screening aims to find tumours that are too small to be felt by you or your doctor. Breast screening won’t stop breast cancer developing, but it will help detect cancers at an early stage, when they're easier to treat.
The NHS breast screening programme offers screening to trans women and to trans men who haven’t had top surgery (chest reconstruction). But you’ll only be automatically invited for screening if you’re registered as a female with your GP. Talk to your GP about screening if you have any concerns.
- Risk reducing surgery – bilateral mastectomy (removal of both of your breasts)
If you have a BRCA1 or BRCA2 gene variant, having surgery (an operation) to remove both breasts may be an option to greatly reduce your risk of developing breast cancer.
Speak to your medical team about options for this surgery. They may recommend that you don’t have this surgery until after you’ve recovered from your ovarian cancer treatment. Risk-reducing breast surgery can't guarantee that you won’t develop breast cancer, but the risk afterwards is small enough that breast screening isn’t needed.
It's likely that you’ll be offered the option of having reconstructive surgery to rebuild both breasts using implants and/or tissue from another part of your body. This may be carried out at the same time as the natural breast tissue is removed or it may be done at another time as a separate surgery.
Surgery will have a very big impact on you both physically and emotionally, especially following an ovarian cancer diagnosis. It’s important that you take your time and discuss all the advantages and disadvantages with a counsellor and your medical team before making a decision.
- Drug treatment and lifestyle choices
In some cases, chemoprevention may be used to reduce the risk of breast cancer. Chemoprevention doesn’t mean having chemotherapy. Chemoprevention is the use of drugs to try to reduce the risk of breast cancer developing. This includes treatment with drugs such as tamoxifen, anastrozole and raloxifene.
Tamoxifen and anastrozole are usually used as treatments for breast cancer, and raloxifene is used to treat or prevent osteoporosis (bone thinning) after the menopause. In this situation they're given to reduce the chance of you developing breast cancer.
Your genetics doctor (geneticist), genetic counsellor or breast cancer specialist can discuss this with you and give you written information on the absolute risks and benefits of chemoprevention before you make a decision. This includes side effects of the drugs and how much they might reduce the risk.
If you have ovarian cancer and have a BRCA1 or BRCA2 gene variant you should be offered advice about other factors that may affect your risk of breast cancer. These include:
The use of the oral contraceptive pill, which can increase the risk of breast cancer. If you stop taking the pill this increased risk of breast cancer gradually reduces again.
The use of hormone replacement therapy (HRT), which, depending on your clinical circumstances, may increase your risk of developing breast cancer. Your clinician should discuss with you whether the increased risk outweighs the benefit, and what other options there are.
Reducing how much alcohol you drink, stopping smoking, and maintaining a healthy weight through healthy eating and exercise to reduce your risk.
Breast Cancer Now has more information about managing your risk of breast cancer
For the most up-to-date information about your treatment options with a genetic variant, please contact our support line.
More about telling your family and the impact of a positive result on them
Impact of ‘variant not present’
If your results show 'variant not present' it means that testing hasn’t found any gene variants.
If you have this result, and don't have a family history of ovarian and/or breast cancer (two or more close relatives with either ovarian or breast cancer), it's most likely that your ovarian cancer was a one-off in your family (or sporadic). It means your risk, and the risk of your children, developing breast cancer and other cancers associated with the BRCA1 and BRCA2 genes is probably similar to the general population.
If you have this result but have a strong family history of ovarian and/or breast cancer, the result can be less helpful. But researchers still don't know all the variants in different genes that may increase the risk of ovarian cancer. It's possible that you have a variant in a different gene not found by this test. This means there is still a level of uncertainty even after genetic testing.
- Can my family members still receive a genetic test if my result is ‘variant not present’?
Predictive genetic testing is a test adult members of your family can choose to have to find out if they have inherited a genetic variant and have an increased risk of developing cancer.
If your result is ‘variant not present’, genetic testing wouldn't be available for the rest of your family. This is because this result makes it less likely that there's a significantly increased risk of developing cancer in your family. If you have a family history of ovarian and/or breast cancer, close relatives may still have an increased risk of developing cancer. There may be options for them to manage this risk, which your genetics specialist can advise you about.
Impact of ‘variant of unknown significance’
You may be told that your test result showed a variant of unknown significance (or VUS). This means that the test has found a genetic variant in a gene but it's not known if it causes an increased risk of ovarian cancer or not.
The majority of VUS results are likely to be harmless differences in a person's genes. But if it hasn't been seen many times before, then it's included in the test report as being of unknown significance.
The number of those who are given a VUS result is decreasing as researchers learn more and more about the different variants that increase the risk of ovarian cancer. It may also mean that your VUS is reclassified as 'variant not present' or 'variant present' over time.
As more is discovered about genes, there's likely to be further information about the VUS in the future. You may like to contact your clinical genetics service to discuss this in a few years' time.
- Can my family members still receive a genetic test if my result is ‘variant of unknown significance’ (VUS)?
If you have a VUS, your unaffected family members won’t be offered genetic testing. But if you have family members who have had breast or ovarian cancer as well, they may be offered testing to help work out the significance of the VUS.
If a VUS is found, your family may feel more uncertain than before. You may find the uncertainty very difficult to understand or deal with emotionally, as it's less clear whether you and other family members have an increased risk. So it's important that you ask your doctor or genetic counsellor for support and advice about the options available to you.
Last reviewed: November 2022
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