By Katie Daly

Copyright hellomagazine

Gareth Halls and his wife, Jenny, never thought that when their then-four-year-old daughter came home from nursery with a high temperature one evening in 2020 that they would soon be looking at a cancer diagnosis. “We assumed COVID had finally caught up with us as a family,” Gareth says as he sits down for an interview with HELLO! during Childhood Cancer Awareness Month. “We had to go to a COVID test centre and have her swabbed, but in the meantime, we went in with some Calpol.”

Over a 24-hour period, Sienna’s temperature failed to come down, leading her parents to call 111. They were told to take her immediately to A&E. Once at her local hospital, Sienna, now nine, was given a course of antibiotics, but five days later, nothing had changed, and she had developed a stomach ache. Account Director Gareth and school teacher Jenny started to become concerned. It was at this time that Sienna was admitted for bloods, and her father received news he never could have prepared for.

Sienna receives a cancer diagnosis

“I asked the doctor if he had had a chance to review the blood results, and he couldn’t look at me. He told me he needed to have a chat with me and my wife,” Gareth recalls. “I felt sick, and out of my peripheral vision, I could see doctors and nurses congregating at the nurses’ station in the ward, looking at me. It was that sinking feeling.”

Gareth was told that they suspected Sienna had leukaemia. “I was broken, I was shell-shocked,” he says, adding that Sienna hadn’t displayed any of the other symptoms of leukemia, such as continuous nose bleeds, headaches, leg pain, bruising, or abnormal sleeping habits. With the help of the nurses and doctors, Gareth broke the news to his wife, who had been at work. “I was not in a good place,” he remembers.

Sienna is taken to Great Ormond Street

After an overnight stay in the hospital, Sienna was taken to Great Ormond Street in London. Due to COVID restrictions, only one parent was allowed to stay with Sienna at GOSH, meaning she didn’t see her mum or big sister Lois, now 11, for three weeks. “She was terrified, she was missing her mummy, she was missing her big sister,” Sienna’s dad says. “With people waking her up at all hours of the night trying to get a vein to take more bloods, she was really scared.”

Sienna soon started on a treatment plan to combat her cancer, being told initially that doctors believed it would last two and a half years. Her treatment involved daily oral chemotherapy, eight pulses of chemotherapy at Great Ormond Street, where she’d have to undergo a lumbar puncture on each occasion, and she’d have chemotherapy injected into her to prevent any of the cancerous blood getting into her spinal fluid or her brain, before undergoing monthly chemotherapy at her local hospital.

Gareth tells us that during her treatment, which also involved being on steroids, Sienna was like a different person, something doctors had warned them might happen. “She’d be shouting ‘Shut up, I hate you, go away’ and that had never been her. In the space of five weeks, she gained three kilograms in weight. She’d finish an adult-sized portion of spaghetti bolognese and say she was still hungry. You thought it was a joke,” he recalls.

Life as the Halls family knew it was tipped on its head with the doctors’ warning them to cancel any holidays and delay any plans while Sienna was receiving treatment. Gareth also remembers how his daughter lost her hair twice throughout her treatment, once as a result of delayed intensification, a particularly “brutal” phase of chemotherapy, he says. “That was really hard, but the team at GOSH was phenomenal,” Gareth says. “There was an amazing nurse on an elephant ward who looked after us called Helen O’Toole. She and her team were incredible.

Sienna was supported by the Play specialists

“When we were at GOSH, I felt safe. When we came home it felt like when you take a newborn child home for the first time and you’re like, ‘Now what do we do?’ which was intensified because of her medical needs. The staff really rallied for me, and when I went home, I felt quite confident because of their coaching, which was nice because I could support my wife and daughter, who were unsure on how to be to begin with.”

The Play team, which is fully funded by Great Ormond Street Hospital Charity (GOSH Charity), also supported Sienna and her father, who stayed with her in hospital throughout her treatment, while her mum looked after big sister Lois at home. “The play specialists were amazing, especially when we went in for the daily procedures where she had to be put under a general anesthetic,” Gareth says.

“They’d normalise every situation and they never lost any energy in doing it, or in trying to create a distraction, trying to make you or your child laugh. They were phenomenal.”

Sienna concludes her treatment

Throughout her treatment, Sienna and her family looked forward to her ringing the bell at GOSH, signalling her being cancer-free. “It was the holy grail,” Gareth says. “Sienna had no immune system; if someone breathed on her with an infection, she would be in the hospital. We had 25 hospital admissions on top of all the hospital appointments, so you’re just thinking ahead to the end and praying you get there.”

“I couldn’t even describe the emotion, the relief, it’s just a surreal feeling [to ring the bell]. It’s a horrible feeling that you’re there, but you’re so grateful to everyone that you’ve got to the end.”

Five years on from Sienna’s cancer diagnosis, she still has six-monthly check-ups, but she is feeling happy and back to her old self. “She is energetic, she is hilariously funny, and she has a wit way beyond her years,” Gareth says of his daughter.

“Having had two years off, she’s got some catching up to do [with school], we’ve got a tutor at home to help her, but that’s the least of our worries. She’s been able to start doing her dance classes, musical theatre, and gymnastics. She’s appeared in a few dance shows, and she’s been able to have birthday parties, start swimming lessons, and all the things that children should be able to enjoy and we often take for granted.”

A special fundraiser

The Halls family is also able to look ahead to this year’s RBC Race For Kids, GOSH Charity’s family fun run, which is raising money to help build a new Children’s Cancer Centre at Great Ormond Street Hospital, on 11 October. “Seeing thousands of people in these vibrant blue T-shirts running, cycling, or scooting through Hyde Park and so many children who have been on the same journey, it’s incredible,” says Gareth. “I think it’s just two percent of cancer research money in this country goes into research for children’s cancers, so it is my hope that this becomes a game changer in the fight against childhood cancer.

“GOSH gave us our daughter back, which is priceless,” he adds. “We’ll do anything we can to raise awareness of that.”

Sienna and her family are taking part in RBC Race for the Kids 2025, raising vital funds to help GOSH Charity build a world-leading new Children’s Cancer Centre at Great Ormond Street Hospital. To get involved or to find out more, visit .