Predictive genetic test for cancer risk genes
Whattesting involves
There are usually two steps to genetic testing:
- Arelative with cancer has a diagnostic blood test to see if they have a cancer risk gene (this normally must happen before any healthy relatives are tested). Their result will be readyfour to eightweeks later.
- If your relative's test is positive, you can have the predictive genetic test to see if you have the same faulty gene. Your GP willrefer you to your local genetics service for the blood test (you'll need a copy of your relative's test results). The result will takeup totwo weeks to come through after a blood sample is taken, butthis may not happen atyour first appointment.This test is fully predictive as a "clear" negative test, which will mean you have not inherited the family high risk of cancer.
The charity Breakthrough Breast Cancer explains the importance of these two steps:
"Without looking at the genes of an affected relative first, testing a healthy individual would be like reading through an entire book looking for a spelling mistake without knowing where the mistake is, or if there is a mistake at all."
When there are no affected relatives available, full testing of BRCA1 and BRCA2 may be possible for those with at least a 10% chance of having a genetic fault. This usually means having a very strong family history of early onset breast and particularly ovarian cancer. It takes four to eight weeks to get the result, but this is not fully predictive as a negative test, so cannot rule out that the problem in relatives is due to a different gene.
Medically Reviewed by a doctor on 21 Dec 2018
Introduction
Cancer is not usually inherited, but some types mainly breast, ovarian, colorectal and prostate cancer can be strongly influenced by genes and can run in families.
What to do if you're worried
Speak to your GP if cancer runs in your family and you're worried you may get it too.Theymay refer you to alocal geneticsservice foran NHSgenetictest, which will tell you if you have inheritedone of t
Pros and cons of having a predictive genetic test
Not everyone who is eligible for the NHS test will want to have it. It's a personal decision, and should only be made after you've had genetic counselling sessions and talkedthrough what having the t
Whattesting involves
There are usually two steps to genetic testing: Arelative with cancer has a diagnostic blood test to see if they have a cancer risk gene (this normally must happen before any healthy relatives a
Whata positive result means
If your predictive genetic test result is positive, it means you have a faulty gene that raises your risk of developing cancer. It doesn'tmean you are guaranteed to get canceryour genes only partly i
Managing your risk
If your test result is positive, you have arange of options to manage your risk. Risk-reducing surgery is not the only option. Ultimately, there's no right or wrong answer about what you should do it
Tellingclose relatives
Your genetics unit will not approach your relatives about your result it will usually be up to you to tell your family. You may be given a standard letter to share with relatives, which explains your
Planning a family
Cancer risk genes can be passed on to any children you have. If your predictive genetic test is positive and you want to start a family, you have several options. You can: Have your children withou
Paying for private testing
If there isn't a strong family history of cancer in your family and the faulty gene hasn't otherwise been identified in any of your relatives, you won't be eligible for the NHS genetic test. You'll h
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