i work in breast cancer genetics (and have genetic breast cancer) but your right they will normally only be able to test affected individuals.... if they identify a gene change they can then look for that specific mutation in non-affected individuals.
a full mutation analysis takes around 4 months and a predictive test for identified genes takes around a month.
its a situation that crops up quite regularly in my job but the reason behind them only testing people with cancer is generally that in somebody who has never had cancer is that a negative result may not be very useful... ie it doesnt tell you whether you just dont have a known gene but are still high risk or if you are negative for one of the know genes.... in both circumstances you would be treated the same so its often deemed not financially beneficial as it wouldnt change your screening.
only about 5% of all breast cancers are genetic. and even where some individuals have a significant family history and fit the testing criteria the majority of genetic tests still come back negative.
you can pay to get tested privately but it costs around £3000 which is quite a significant amount of money to most likely find out that they cannot find a gene... but some people would still rather pay to do this.... a negative result doesnt mean that you are low risk.
some of the other risk factors are the age your relatives actually were diagnosed at... if they were all in their 60s then this is the age you would normally expect people to get breast cancer at (the why they screen at that age) but if they were in their 30s and 40s then this could indicate there is a mutation.
in terms of screening, now taht more and more people are having prophylactic surgery it means that there isnt always a 1st degree relative who is affected (another criteria for testing) eg your daughter would only have a 2nd degree relative affected that is your mum so in terms of screening would normally be excluded... however you would hope your local services do take into account the fact you have had preventative surgery and still screen your daughter.... screening would normally start 5 years younger than the youngest affect person or form age 35/40.
Thanks for that. Everything I read does say that they need to do the test on someone with BC. Hopefully things have moved on. I have a sister who also has a daughter and obviously their risks are the same as mine and my daughters. My sister's daughter has just contacted her GP who is referring her to a Genetics Service so we will wait to see what they say.
I'm pretty certain they can do the test without involving other relatives. A scientist friend of mine worked on the human genome project a few years back and he told me a test had been developed where they could identify the gene in an individual. I'm sure the BCC helpline would be able to advise you about your daughter.
Hi moho and welcome to the BCC forums
I am sure you will receive a wealth of valuable replies here from your fellow users, in the meantime I am posting to the BCC publication 'Breast cancer in families' which you may find useful to read:
If you wish to discuss any of your concerns with one of our helpliners please call 0808 800 6000, weekdays 9-5 and Sat 9-2.
both mu mum and grandmum and her sister all died of breast cancer over 20 years ago. 8 years ago I realised that I needed to do something about this so went to see genetic specialist who said that before I could be tested they would need to test a living relative who had bc. My aunt (who has since died) had the test and we waited 2 years for results. They were inconclusive. I have sice had a double mastectomy and ovaries removed to reduce my risks. Although I had not been tested they said my risk factor was 1 in 3. Do I understand correctly that you have to have a living relative with bc to have the test (and if positive they can then give you the test to compare with?). Have things changed and they can now detect the faulty gene even if they don't have someone to compare with? I have a daughter who is also at risk and as I have taken myself out of the equation don't know what to advise her to do. By the way surgery was the best thing I have done, the recontruction I had at Birmingham Women's hosplital is fantastic.