Should I have the breast cancer gene test?

A teenage girl whose family has "been cursed" by hereditary breast cancer for generations faces a dilemma - should she be tested for a mutated gene which could cause the disease?

"It's not so much that I'm scared to get the test, or I'm scared for the operation," said Josie Bellerby, an 18-year old from York.

"It's a decision. If you go and get the test done you can never take it back, so it's just whether or not you want to risk feeling like part of your body might kill you."

Josie comes from a family where breast cancer has claimed the lives of her grandmother and great-great-grandmother. Her mother, Julia, had a preventative double mastectomy when she was younger after she found out she had an increased risk of cancer.

Josie has two sisters, Lucy and Emma, and the possibility that any of their daughters has a faulty gene has been difficult for parents Julia and Jules.

Julia said: "I lost my mum to cancer, I could not bear to lose a daughter to cancer. That just doesn't feel like something I could cope with at all.

"It just makes me sad because it is all becoming kind of real now. This thing that I so dreaded when I went through it myself, that you'd all have to face it and here it is, it is actually happening."

"They shouldn't have to be thinking of things like breast cancer, at their age," said Jules.

Josie wants to go drama college next year, but fears that if she has the test, the results might affect her plans.

"I never thought about the future. The furthest in the future I thought about was when is my next audition or, when are my exams coming up?

Jules and Julia's three daughters, Emma (l), Josie and Lucy (r) have all considered having the genetic test

"I feel like I am possibly being forced to grow up a bit faster because of this thing.

"I think it shocked our family quite a lot because we always just thought 'Oh, do you know what? We don't need to think about this,' but actually you do and it's happening sooner than we allowed for."

If someone carries the mutated genes BRCA1 or BRCA2, it can mean they have an up to 80% chance of developing breast cancer.

Both men and women carry the BRCA gene and children inherit one copy from each parent. Even if you only inherit one rogue copy, that will increase the cancer risk.

So for each child of a couple where there is one parent with a working gene and one with a flawed version, there is a 50/50 chance of inheriting the mutated gene.

But Josie's mother Julia worries she might be more scared if her sisters' results are clear.

"It's almost like, it's like Russian roulette, so if Lucy and Emma don't have it then you might think 'Oh God it is bound to be me'."

But Josie said she was prepared for that game of chance. "The chances of three girls possibly carrying a gene and for then none of them to have it just seems like illogical.

"Me and my sisters are so close now, it scares me sometimes. (But) the results of the test may make us either drift... make two drift apart or two come close... which affects that bond," she said.

At 23, Josie's big sister, Lucy, decided to have the test.

Lucy said: "I'm definitely not ready 100%, I don't think I would ever be 100% ready... but I think I'm at a place where I can cope with it."

But Josie feared her own decision could be changed by her sister's results.

"If I don't handle it very well with Lucy, then how am I going to handle it when it's actually me that's going through it?" she said.

The middle sister, Emma initially decided not to take the genetic test. She started the process but felt she was too young. But she has since reconsidered.

Receiving test results positive for the mutated gene often starts a process of decision-making about other things - like whether to have preventative surgery or partake in drug trials.

Mother Julia had known straight away what she would do. "I knew long before I had the test that if I had the gene, I would have surgery. And my instant reaction was just get rid of them (my breasts), they can kill me, let's get rid of them."

Professor Gareth Evans, from the Genesis Prevention Centre said the clinic was developing new treatments to take away BRCA1-related risk.

We are starting to actually treat people with Tamoxifen," he said. "So that is an old drug, that is nothing new, but what's new is that this is being offered as a preventative.

"Tamoxifen has been shown, with five years treatment, to reduce the risk by 40%."

And a group of drugs called "Parp" inhibitors are also being trialled at the moment.

"A Parp inhibitor is a drug that specifically targets cells which have lost the BRCA1 gene. We can actually kill the cells before they become cancerous. Now, if the drugs work perfectly it will normalise your risk of getting breast cancer, because it will effectively take away the BRCA1."

These options helped Josie decide that she wanted to take the test.

"If it's not a good result and I have BRCA, then, I'll cope with it because you just do suck it up, get the news, and deal with it.

"It doesn't need to be something that rules my life. It doesn't need to be something that I think about every day, I could still be me.

"I can still have a laugh and enjoy being young, but just be a little bit more responsible, and just be a little bit more aware."

Josie: My Cancer Curse is on Thursday 14 July at 2100 BST on BBC Three or watch again on BBC iPlayer.