This bubbly young mum, who looks like the girl next door, is the only McGrath Breast Care Nurse whose job is solely to support women with metastatic or stage-four breast cancer – the incurable type, where people present with secondary cancer in places such as the bones, lung, liver or brain.

Each patient – and she sees an average of one new patient a day – is special to her.

"Everyone I meet could be my sister, could be my mum, could be someone close to me," she says.

"I just think, God, what would I want for them? I'd want excellent, timely health care, the right stuff, the right information. I'd want them to be empowered, to be informed and to have someone around who gives a damn."

Kerryn's metastatic position at Canberra Hospital is unique. And so is Kerryn.

"I'll never forget her help," says 26-year-old Sophie Brown, whose mother, Ann Muller, a Canberra public servant, was cared for by the McGrath nurse from her diagnosis with the terminal disease in May 2012, to her death aged 53, on 6 November 2013.

Sophie's thoughts are echoed by Trevor Hickman, whose diplomat wife, Amy, 44, died on 6 September 2014, leaving two young children, Audrey, now eight, and Eli, six.

Trevor, who works as an analyst in local government, chose Kerryn to give a eulogy at his wife's funeral. "In the middle of all this shitty luck, I thought about who had had the most impact on the last three and a bit years of Amy's life. Kerryn stood alone," he says. "The relationship Amy had with Kerryn was just incredible. She was a constant source of support and help."

Kerryn, 39, works three days a week in her McGrath role. She's an ex-soldier's daughter who moved to the nation's capital with her South Australian parents and two sisters when she was 11.

She took up the position in July 2009, bringing to it a wealth of experience in breast care, medical oncology and – from her time as an educator at the Canberra hospice where she did her master's degree in palliative care – "good skills for talking about death and dying and caring for people who are going to die".

"The outcome is never great for people with secondary breast cancer," she says, "but it's lovely to be able to follow these people through. You really get to know them over the years. If I can make a difference and give them help and a different quality of life up to that point, that's what's important to me."

The work is challenging and, at times, draining.

"Some days it is terribly, terribly sad," she admits. "I remember my first day back after maternity leave. A lady in her 40s was dying and I sat with her mother and her heart was breaking. She said, 'That's my baby in there, that's my baby dying.' It doesn't matter how old you are, you're always someone's baby."

Kerryn, who has two sons, Ethan, six, and Callum, four, with her husband, Chris, brings enormous humanity to her role.

It was Kerryn's own family experience with breast cancer that prompted her to aspire to become a McGrath Breast Care Nurse. "I remember seeing Jane and Glenn McGrath selling the tomato sauce – the time they turned the bottle pink – and I always thought, Wow, it's great they're doing this. I hope I can be one of those nurses one day because my paternal aunty died of breast cancer in 2002 when I was still working at the Royal North Shore Hospital in Sydney. The McGrath Foundation started in 2005 and I'd moved back to Canberra by then, but the issue was still close to home.

"My aunty was the cool aunty and when she died she had no access to anything. She lived in Port Lincoln, South Australia, and had to travel 600 kilometres to get her treatment and see the doctor – all with very little support – so I was excited when they got the Port Lincoln breast care nurse a few years ago. I thought that was fabulous. I thought, Here's this organisation that's going to put nurses in regional centres and they're going to make sure people have professional support, because my aunty had nothing."

Sophie Brown was just 18 and her brother, Hugh, 11, when their mother Ann was first diagnosed with breast cancer in September 2007. Sophie became her mother's primary carer and remembers events unfolding "very quickly". But she has no recall of there being a breast care nurse on hand to help.

"It was completely out of the blue and very shocking," she says. "Mum was only forty-seven. She was diagnosed with triple-negative breast cancer, had four rounds of chemo, then a mastectomy in December, then two more rounds of chemo, then radiotherapy.

"She went into remission in early 2008 and went back to work in April."

In 2012 their mother's cancer returned. "It was a really big shock because she was almost at five years cancer-free and the cancer had metastasised so she was never going to get better. She was terminal, essentially, which was another big shock."

This time the treatment was very different, however, the Brown children had their backup: Kerryn.

"She was amazing," says Sophie. "She made the whole process so much easier. Mum said it was like having your own personal liaison [officer] because it was so difficult to get scans and drugs and meet up with specialists. Kerryn was a magician at working her way through it all. She was really clear about what we needed, she answered our questions and she was so warm and caring on top of that.

"I think Kerryn was very aware of our unique situation, of how it was Mum and me and Hugh. She knew I was Mum's primary carer and that it was a bit awkward at times. She took our situation on board and communicated the services that would be good for us. She'd chat with us while Mum was having her chemo to help the time go faster and that could take three or four hours. She would chat about normal things – TV shows, movies, sport, her kids, what was going on. You were still in that environment, but it was a breath of fresh air."

Trevor Hickman admits he is still raw with grief. In 2014, he watched his wife, Amy, succumb to secondary breast cancer. "I still feel Amy is with me and that she is going to come back at any minute," he says. "I'm not going mad. That's how it feels. And if I feel like that as an adult who understands what death is, what hope do my children have? They must feel the same way."

Amy, a vibrant, highly regarded diplomat who worked for the Department of Foreign Affairs and Trade, was mother to Audrey and Eli, and lived a very healthy, very active life.

No-one knows what caused the cancer. Her oncologist told Trevor, "It's just shitty luck," which is something he holds on to. It had nothing to do with what Amy did or didn't do.

The first sign of Amy's disease was pain in her right hip, which she put down to carrying around her then 18-month-old son, Eli. It was thought to be arthritis or bursitis and the worst she feared was a hip replacement. However, an X-ray and biopsy just before Christmas 2010 revealed it was a secondary breast cancer that had spread to her bones from her right breast.

In one fell swoop, this fabulous woman who lived life to the full and put others first, was told she had stage-four, incurable cancer and that the focus of any treatment would be palliative only, to help her live as long as possible.

Trevor says he knew within a week or two of Amy's diagnosis that Kerryn was "a very, very important person in the mix of things".

"Amy and I knew very little about cancer and then we had immediate access to someone who was a constant source of help and support. Kerryn was quick to give Amy her mobile number and tell her to ring any time. Kerryn also has a young family so we felt a lot of empathy there. Even now, she'll say, What are you going to do over the school holidays? Your kids can have a play date with mine if you want to leave them. It's an incredible thing."

Trevor remains in contact with Kerryn. "Yes, I went in a couple of times after Amy died. I took Kerryn in a cheesecake. We've swapped emails and she's volunteered for me to drop the kids over."

Kerryn is still available to talk. She extends a helping hand to many husbands whose wives are or have been patients.

"They come back for some familiarity," she says. "They might return weekly for a few weeks and then peter out. I figure their lives are getting busy and they are managing things. I still hear from them occasionally but that intensity lessens. They're so used to coming here to the hospital when their wives are sick that it's a comfort."

She doesn't cut anyone adrift. "No, of course not!" she says, horrified at the very suggestion. "They can see me, or ring and ask questions – anything. They visit the treatment nurses as well because they have known them for years. They may have known them for three years, and often they are in twice a week for treatment, maybe once for a blood test and the next day for some chemotherapy.

"Advanced breast cancer can be a tragic area [to work in]. I have to remind myself that 95 per cent of women with early-stage breast cancers in Canberra are alive and well in five years, and disease-free. The overall survival for patients with secondary breast cancer varies greatly. Women with advanced disease live for an average of two and a half to three years.

"It's getting better. Last year we got four new drugs – two are Herceptin drugs we usually give with chemotherapy – and there is another that is used with anti-hormone therapy that came out recently so that's helped because there are more treatments we can try."

"Some women say they don't want to go on. They've had enough. A lot say, 'I did chemo years ago and they don't want to do it again.' I say, 'Yes, I understand completely. We'll just keep an eye on you'.

"Usually, we try to do all the anti-hormone treatments first, which will contain the cancer to an extent. We get palliative care involved if they're not going to do chemo but, sometimes, you need a really good dose of chemotherapy to get things under control.

"Back when you've got early breast cancer and it's curable, you are given a big whack of chemo every three weeks and it knocks you for a six. We don't use that in advanced breast cancer. What we have learnt for those patients is that a smaller dose of chemo given more often is equally beneficial and can help quality of life. You do that every week for three weeks. You might get one week off and repeat for six months. That's a lot of time in the chemo room, plus you have a weekly blood test to make sure you're fit enough to have chemo.

"Patients can opt out at anytime, which is fine, but I explain that they might just feel a lot better. We can reduce swelling on their liver and make them feel well enough to get back onto the hormones and then, who knows how long they may get?"

This is an edited extract from Take My Hand: Inspiring nursing stories from the McGrath Foundation, by Jo Wiles. Viking. $32.99.