When Great Ormond Street Hospital opened 150 years ago this week, children with leukaemia had almost no chance of surviving. Now sufferers have real hope for the future

Tracey Forder's son Piers wasn't quite himself. He was sleeping for a bit longer than usual, had been sick a few times, and had gone off his food. But he was 18 months old – nearing the terrible twos – so his mother saw no reason to be worried.

Then, one evening, she gently pulled down his eyelid, wondering if perhaps he might be anaemic. There was no colour difference between the outside and inside of the eyelid. She and her husband Nigel decided she should take him to the doctor on Monday.

Her GP suggested they go to Accident and Emergency. At eight o'clock that evening, two consultants and two doctors walked into the room where Tracey was waiting. They told her Piers had leukaemia and that she and her son should leave for Great Ormond Street Hospital immediately.

"When they told me, it felt like having my whole life taken away from me," says Tracey, 30, from Weybridge, Surrey. "I thought, 'That's it. I'm going to sit and watch my child die'."

But under a year later, the toddler is not only still alive, but in remission from his cancer. There are no certainties, but he is expected to beat it completely over the next few years. Leukaemia is now among the most curable of childhood cancers – and the hospital that treated Piers, Great Ormond Street, can claim a large slice of the credit for these saved lives.

Tomorrow, Great Ormond Street celebrates its 150th birthday. When it opened there was almost no hope for children with this form of cancer: they would die within a few weeks of diagnosis. Little changed for 100 years. In 1968, Professor Roger Hardisty, then head of clinical services for children with leukaemia at the hospital, decided to contact former child patients who had been cured. He found only 83.

Shortly afterwards, he began the first national trials in paediatric acute leukaemia. Ever since, his hospital has been at the forefront of improving treatment and raising cure rates for the 430 UK children affected by the disease every year.

Piers has a rare form of the cancer, acute myeloid leukaemia (AML), which is more deadly than the commoner acute lymphoblastic leukaemia (ALL). But even so, his chances of survival were 60 per cent. Around 80 per cent of children with ALL are now cured.

The fruits of Dr Hadisty's labours began to be seen in the early 1970s. In 1973, 11-year-old Margaret Duffin was diagnosed with leukaemia and admitted to Great Ormond Street. Chemotherapy – the administration of large quantities of drugs to treat the disease – was in its early stages and blood transfusions from relatives with matching blood types were used as a way to replace cancerous blood.

Professor Judith Chessells had just started working at the hospital at the time. "I remember Margaret very well," she says. "She was an older girl who understood what was going on. She was desperately ill during her induction treatment, and then she got a life-threatening infection but mercifully survived. After that, she remained on treatment for a couple of years as an outpatient and stayed well and became a young mother. I had a photograph of her with her young daughter that I would use to demonstrate the curability of leukaemia."

Thirty years on, Margaret is a 40-year-old mother living in Dagenham, Essex, and Professor Chessells is the chair of the Leukaemia Research Fund at the Institute for Child Health at Great Ormond Street. During her career at the hospital, Professor Chessells and her team have been responsible for several significant studies into childhood leukaemia. In 1990, she completed a national trial confirming the benefits of intensified chemotherapy for all children with ALL. Her colleague Dr Ian Hann's trials into AML between 1990-7 produced the best survival rates in the world at that time. It is this research that helped to save Piers Forder's life.

Only three days after his diagnosis, Piers started chemotherapy that continued intensively for the next five weeks. "He was very sick at that time," says Tracey Forder. "It was very difficult to watch because there was nothing I could do. He lost his hair in week three. It was gorgeous blond hair – he looked like a cherub – but when the wind blew in his direction, the hair would fall out. I got it all shaved off immediately. It was then he started looking like a cancer sufferer to me."

When a child has leukaemia, his or her bone marrow produces diseased white blood cells that can't fight infection as they normally do. Chemotherapy aims to wipe out these cells as fast as possible, but leaves the child with no immunity against disease. This is the most dangerous time. Piers had a temperature of above 40C for four days during one such infection. In 1973, Margaret Duffin had slipped into a coma while fighting pneumonia.

When his initial period of chemotherapy was over, Piers was allowed home for a week. "He was running around and happy and ate Weetabix three times a day for the whole week," says his mother. "It was then that I thought, 'He's turned the corner'. For the rest of his treatment, he was happy and smiling."

Tracey's instincts were correct. If a child survives the initial treatments, their chances of being cured increase dramatically. "Children with cancer and leukaemia have one main chance of being cured and that is getting the management right the first time around," says Professor Chessells. "This rescue treatment is always more complicated, more difficult and, sadly, often less successful with children."

Great Ormond Street Hospital was the first children's hospital in the English-speaking world when it opened in 1852. Professor Chessells stresses the importance of a children-only hospital in improving the survival rates of children. "I, and all my colleagues in paediatrics, believe that all children with cancer and leukaemia should be treated at a dedicated tertiary-care children's centre," she says.

Nursing children with cancer also has unique demands. "The nurses have a very difficult job," says Tracey. "They are not just nursing the children, but the adults as well. Hysterical parents can come across as selfish and overdemanding. The nurses at Great Ormond Street were everything that you'd want them to be. I don't think there was one moment when I didn't have complete respect and confidence in them. I'd never left Piers with anyone before, but there I was happy to go and grab something to eat and leave him with them."

Margaret Duffin, on the other hand, had her own way of making life difficult for the nurses. "I used to hide from the guy who came to take the blood," she remembers. "The worst thing about being ill was all the drugs you were given when you just wanted to be alone." But despite the constant invasions of her body and privacy, she has nothing but praise for those that looked after her. "It must have been the worst time of my parents' lives," she says. "But I had a great time. I was never left on my own, so I was never lonely."

Great Ormond Street also leads the field in ensuring that the treatments given to the very young do not harm them in later life. The hospital was one of the first groups to look at the long-term effects of treatments such as radiation. This research showed that girls receiving cranial irradiation at a young age often failed to grow normally when they reached adolescence. As a result, radiotherapy is now avoided as a first-line treatment.

In the future, Professor Chessells hopes to provide individual treatments for everyone with leukaemia. Using cytogenetics, she and her team can now identify groups of children who will do well with the standard therapy and those who will not. As a result, their treatment can be tailored to their needs, increasing their chances of survival. Eventually, she hopes this will lead to less toxic treatments and improved tracking of any residual cancer cells after the first phase of treatment.

For Tracey Forder, the future is uncertain but she is increasingly hopeful. "There is a 30 per cent chance Piers will relapse, and that is most likely in the first year. There isn't a day goes by when I don't think, 'What if?'" she says.

"It takes five years before you are cured, but Piers is running around with bundles of energy at the moment. He's got colour in his cheeks again and his hair looks good. He likes playing in the park and going on the swings; and he loves heavy machinery. We often have to go and watch the diggers and bulldozers. He's a normal two-year-old."

For further details, or to make an online donation to Great Ormond Street Hospital: www.gosh.nhs.uk