The close collaboration between the Paul Scherrer Institute PSI and the University Children’s Hospital Zurich for the benefit of children suffering from cancer began 20 years ago. Thanks to this collaboration, even very young patients in Switzerland can be irradiated with protons. More than 800 children and adolescents have already benefited from this unique success story.

On 5 July 2004, a young child was irradiated under anaesthesia at PSI’s Centre for Proton Therapy for the first time. The toddler was little more than two years old and suffered from a soft tissue tumour in the socket of his eye. This treatment would not have been possible without the collaboration of the Department of Anaesthesia at the University Children’s Hospital Zurich. Their specialists looked after the young patient on PSI’s premises in Villigen, ensuring that he literally slept through his radiotherapy.

“The interdisciplinary collaboration between the Children’s Hospital and PSI is exemplary, in my opinion,” says Georg Schäppi, CEO of the Children’s Hospital Zurich. “Here, the right people from different professions are working together in a technically perfect setting, and as a result they are performing small and large miracles.”

Between 1999 and 2004, PSI’s Centre for Proton Therapy had been treating children and adolescents with cancer from the age of seven upwards, but the real breakthrough in radiotherapy for young patients came once the Children’s Hospital Zurich lent its support. Since then, it has been possible to treat very young children, too. Because, unlike adults, these young patients usually require anaesthesia.

“Particularly when performing high-precision radiotherapy, like proton beam therapy, it is important that the patient doesn’t move during the treatment,” explains Damien Weber, Chief Physician and Head of the Centre for Proton Therapy at PSI. “However, very young children find it extremely difficult to keep still for the entire duration of the procedure.”

The first in Europe

At the time, only two centres in the entire USA were also performing proton therapy on young children under anaesthesia: Loma Linda in California and Boston. “Thanks to its collaboration with the Children’s Hospital, PSI has been able to offer this as a standard form of treatment in Europe since 2004,” says Damien Weber proudly.

The children are sent to sleep by inducing a light form of anaesthesia, so that they lie still while the proton beam goes about destroying the tumour. The sedation is adjusted to prevent the young patients from coughing or moving around, but remains light enough to allow them to breathe unassisted. The anaesthetic team monitors the children and their bodily functions throughout the radiotherapy from an adjacent room.

Overall, half the children and adolescents who receive radiotherapy at PSI are given an anaesthetic. The youngest patient at PSI was three months old: a child that had been born with cancer.

Proton therapy for children

Like the photons in conventional radiotherapy, protons kill cancer cells. However, protons are particles that have mass and charge, and the depth to which they penetrate human tissue is precisely determined by the physical conditions. They lose very little of their energy as they pass through the body, releasing most of it on reaching their target, the tumour. Here they literally come to a standstill.

Children with cancer can benefit particularly from precise proton therapy, as Damien Weber explains. This is because children are at higher risk of sustaining long-term radiation damage, which they will have to deal with for the rest of their lives: the potential complications include tumours induced by the radiation itself, loss of hearing, impaired growth and learning disabilities.

60 to 70 children and adolescents are treated at PSI every year; to date, more than 800 have been treated overall. The majority of these young patients suffer from tumours of the brain and spinal cord. The second most common type are sarcomas, cancers that originate in connective or muscle tissue.

PSI also works very closely with the oncology department at the Children’s Hospital Zurich. “Our close working relationship allows us to give our patients the best possible treatment,” says Michael Grotzer, Medical Director of the Children’s Hospital Zurich. “In our joint tumour board meetings, we decide together which type of radiotherapy is best for which child and within what time frame; that’s how we develop the treatment plan.”

Thanks to its collaboration with the Children’s Hospital, the Centre for Proton Therapy at PSI is able to treat not only children from Zurich, but also young patients from other cancer centres in Switzerland and even from abroad. “PSI makes it possible to provide the best currently conceivable treatment using protons,” says Michael Grotzer. “Together, we are able to offer children in Switzerland world-class cancer treatment – something we can be very proud of.”

Familiar atmosphere

The collaboration between Zurich’s Children’s Hospital and PSI is now running absolutely smoothly. Every weekday, a senior anaesthetist and an anaesthetic nurse from the children’s hospital are sent to PSI. They administer the anaesthetic, monitor the young patients and ensure they receive the best possible care. “We may work for different employers, but that doesn’t change the fact that we’re a really good team,” says Alessia Pica, senior radiation oncologist and Head of Paediatrics at the Centre for Proton Therapy.

“Our specialists face very specific challenges,” adds Georg Schäppi from Zurich’s Children’s Hospital. “The children concerned and their families have been through a great deal. The team from PSI and the Children’s Hospital provides remarkable care for the children and is sensitive to their specific needs. I am deeply impressed by that.”

At the Centre for Proton Therapy, work starts at 7.30 in the morning, and the first child receives radiation treatment at 8 a.m. – up to seven young patients a day, in total. “We take a lot of time for the children,” says Ilka Schmidt-Deubig, Head of Anaesthesia at the Children’s Hospital Zurich. “We want them to feel comfortable.” The team invites parents to bring their children in at least half an hour before the radiotherapy session so that they can arrive and settle in; a specially equipped playroom helps them feel at home. Later, the parents, siblings, grandparents, aunts and uncles are allowed to accompany the child to the anaesthetic room and hold its hand while it falls asleep.

“After a week or two, even traumatised children know they can trust us,” says Ilka Schmidt-Deubig. Sometimes her working day at PSI doesn’t end until late in the evening; because no matter how well the team has organised everything, plans often have to be changed when treating children. “Treating children with cancer is tough, and the job can feel like a constant battle,” adds Alessia Pica. “But when the children end up doing well, and they and their families are happy, and hopefully there’s a happy ending – then it’s a wonderful job.”

Text: Brigitte Osterath