An alternative cancer treatment is just as effective as radiotherapy but as fewer damaging side effects on children, a new study has found.

Proton beam therapy became the subject of national debate in 2014 when the parents of a five-year-old boy were detained by police for taking him from a British hospital to seek the treatment abroad.

Brett and Naghemeh King had disagreed with doctors at Southampton General Hospital over how to treat their son Ashya’s medulloblastoma, a type of brain tumour.

Ashya King goes back to school

The NHS did not offer proton beam therapy in the UK at the time and had refused to refer them abroad, prompting the parents to travel to a specialist centre in the Czech Republic themselves.

Last March, Mr and Mrs King announced that their son was in remission and Ashya returned to school full-time this month.

A study published in the Lancet Oncology Journal said radiotherapy and proton beam treatment had similar survival rates for medulloblastoma but found that it the less common method has several advantages.

The authors, led by Dr Torunn Yock from the Massachusetts General Hospital in the US, said: “Our findings suggest that proton radiotherapy seems to result in an acceptable degree of toxicity and had similar survival outcomes to those achieved with photon-based radiotherapy.

“Although there remain some effects of treatment on hearing, endocrine, and neurocognitive outcomes - particularly in younger patients - other late effects common in photon-treated patients, such as cardiac, pulmonary, and gastrointestinal toxic effects, were absent.

“Proton radiotherapy resulted in acceptable toxicity and had similar survival outcomes to those noted with conventional radiotherapy, suggesting that the use of the treatment may be an alternative to photon-based treatments.”

Dr. Vladimir Vondracek operates a machine in a proton therapy treatment room at Proton Therapy Center in Prague, Czech Republic (AP)

The study, published in the Lancet Oncology journal, listed common “toxic” effects of radiotherapy on the heart, lungs and stomach were not seen in those undergoing proton treatment.

They analysed 59 patients with medulloblastoma - the most common kind of malignant brain tumour in children - aged between three and 21 from 2003 to 2009.

Fifty-five of the patients had the tumour partially or completely removed through surgery, while all patients received chemotherapy as well as proton beam therapy.

Three years after treatment, 83 per cent survived without the cancer getting worse, falling to 80 per cent after five years.

In terms of side effects, around one in seven had serious hearing loss after five years and 55 per cent had problems with the neurendocrine system, which regulates hormones.

Dr Yock told BBC Radio 5 Live: “The major finding is that proton therapy is as effective as photon therapy [conventional X-ray radiotherapy] in curing these patients and what is also very exciting is that it is maintaining these high rates of cure but doing so with less late toxicity, which has dramatic quality of life improvements.”

In pictures: Ashya King's case Show all 22 1 /22 In pictures: Ashya King's case In pictures: Ashya King's case Ashya King Brett King, back left, and Naghemeh King, right, accompany their son Ashya King (5) center, as he arrives for pre-cancer treatment examinations at the Motol hospital in Prague, Czech Republic In pictures: Ashya King's case Ashya King Ashya King (5) arrives for pre-cancer treatment examinations at the Motol hospital in Prague, Czech Republic In pictures: Ashya King's case Ashya King Brett King, father of five year old Ashya King, talks to members of the press after holding a press conference at his lawyer's office in Seville, Spain In pictures: Ashya King's case Ashya King Brett and Naghemeh King, parents of Ashya King, attend a press conference in Sevilla, Spain. The British parents are heading to see him at a hospital in southern Spain following release their from custody after United Kingdom authorities dropped accusations of child cruelty against them In pictures: Ashya King's case Ashya King British couple Brett (L) and Naghemeh (2L) King leave Soto del Real Prision in Soto del Real, near Madrid, Spain In pictures: Ashya King's case Ashya King Brett King leaving Soto del Real prison near Madrid, Spain after British authorities dropped the case against him and his wife for taking their son Ashya from Southampton General Hospital without the consent of doctors In pictures: Ashya King's case Ashya King Naghemeh King leaves Soto del Real Prision in Soto del Real, near Madrid, Spain In pictures: Ashya King's case Ashya King Ashya King in hospital with his mother In pictures: Ashya King's case Ashya King Journalist work outside the Materno Infantil Hospital where Ashya King is hospitalized in Malaga, Spain In pictures: Ashya King's case Ashya King Ethan Dallas and Sanjay Ganatra, friends of the family, deliver a petition of over 100,000 names calling for his parents' release from a Spanish jail PA In pictures: Ashya King's case Ashya King Spanish judge Ismael Moreno arrives to the National Courts to take statement to the parents of Britain's five-year-old boy Ashya King, in Madrid, Spain In pictures: Ashya King's case Ashya King Ashya King parents's lawyer, Juan Isidro Fernandez Diaz, arrives at the National court in Madrid AP Photo/Andres Kudacki In pictures: Ashya King's case Ashya King Spanish policemen stand guard as a police van carrying the parents of Ashya King arrives at the courthouse in Madrid JAVIER SORIANO/AFP/Getty Images In pictures: Ashya King's case Ashya King Ashya King’s parents after their court appearance BBC In pictures: Ashya King's case Ashya King Ashya King's father explained why he took his son to Spain in a video uploaded to YouTube In pictures: Ashya King's case Ashya King This photo of Ashya King being examined by doctors in hospital was posted on Facebook by his brother, Naveed Facebook/Naveed King In pictures: Ashya King's case Ashya King Ashya King and his brother Naveed Facebook/Naveed King In pictures: Ashya King's case Ashya King Ashya King on a hospital bed Facebook/Naveed King In pictures: Ashya King's case Ashya King A CCTV still issued by Hampshire Police of Ashya King with his father Brett King at around 4pm yesterday PA/Hampshire Police In pictures: Ashya King's case Ashya King The exterior of Southampton General Hospital where Ashya King, who has a brain tumour was taken by his parents from the hospital without the blessing of doctors In pictures: Ashya King's case Ashya King Hampshire Constabulary said there are 'serious concerns' for the life of Ashya King as he needs constant medical care. Officers said his parents - Brett, 51, and Naghemeh, 45, - boarded a cross-Channel ferry from Portsmouth to Cherbourg at 4pm yesterday with Ashya's six siblings PA/Hampshire Police In pictures: Ashya King's case Ashya King Ashya King, who has a brain tumour and was taken by his parents from hospital without the blessing of doctors

Proton therapy is a highly targeted treatment often used on hard-to-reach cancers and has a lower risk of damaging other body tissue.

High-energy protons, rather than the photons of conventional radiotherapy, penetrate the skin and release energy at the tumour, destroying the capacity of cancer cells to replicate.

Dr Kieran Breen, from the Brain Tumour Research Foundation, told the BBC more research is needed.

“In the longer term, we need to try and understand what effects it will have on people and there are many other forms of tumour both in the brain and in other parts of the body,” he said.

Proton beam therapy is currently only available to treat eye cancers in the UK, with the NHS sending patients for other types abroad, but several new centres are due to open from this year onwards.

The Department of Health has pledged to offer the treatment to up to 1,500 cancer patients at hospitals in London and Manchester from April 2018, following investment worth £250 million.