New approach to otherwise fatal early-childhood brain tumour improves survival by up to 50 per cent

Curtis Brown, Jr. (CJ) is an active almost-10-year-old who loves snowboarding, skateboarding and BMX biking. Growing up in a bilingual home, he has been fluent in English and French since he learned to speak as a toddler.

In the fall of 2007, two-year-old CJ began to show signs that something was happening to his brain. He was quickly diagnosed with what was then known to be a lethal cancerous brain tumour. A decade ago, very young children with rhabdoid tumours would not have lived a year following diagnosis.

Today, some children like CJ are living longer lives, thanks to a shift in the way some of these tumours are being classified, and ultimately, treated. A team of researchers led by The Hospital for Sick Children (SickKids) has defined a way treat patients with rhabdoid tumours using personalized medicine and high-dose chemotherapy resulting in a 40 to 50 per cent improvement in survivability. The study is published in the April 14 online edition of The Lancet Oncology.

Rhabdoid brain tumours, which are typically found in children under three years old, are highly malignant and until recently were thought to be incurable. Typically, tumours of this nature are treated with surgery, multiple chemotherapeutic drugs and whole-brain and spine radiation, which can effectively treat a small percentage of patients.

While radiation therapy carries risks for all children, the decision to use radiation on very young children (under the age of three) can be an impossible choice for doctors and parents. In some centres, like SickKids, radiation is not offered to children this young because the treatment would result in catastrophic damage to their developing brains. In most cases where radiation would have been the only option if chemotherapy and surgery were not enough to put a baby or toddler into remission, there were no other tools to treat the child’s cancer.

“We needed to find an innovative way to treat these patients that did not involve radiation, but did not compromise survivability,” says Dr. Annie Huang, senior author of the study and Staff Oncologist and Senior Scientist at SickKids. “This study tells us that radiation therapy might not always be necessary.”

In what is believed to be the largest study of its kind, researchers looked at 259 tumours from 37 international health-care institutions. They were able to classify the tumours into subgroups based on genetic analysis and biological and clinical risk factors such as the location of the tumour and whether it had metastasized. Through this study they were able to understand which groups of patients would likely benefit from aggressive chemotherapy without radiation. The investigators showed that up to 60 per cent of children with good genetic and clinical features can achieve long-term (more than five years) survival with chemotherapy alone, while some children with poor genetic and clinical features fared poorly even when given radiation treatment.

By studying such large numbers of these rare tumours, the investigators have identified a group of patients with good genetic and biological characteristics that may ultimately result in long-term survival even with less aggressive and “smarter, tailored” treatments. The study has also provided significant new information that is already helping the researchers look for newer drugs for those patients whose cancers persist even with the currently-available intensive treatments including radiation.

And although rhabdoid tumours are rare (affecting about 10 children per year in Canada), Huang says this research can help scientists better understand how to treat young patients with other paediatric brain tumours. As related tumours can also arise outside of the brain in adults and children, the researchers are optimistic this will inform advances for other cancers.

Nov. 29, 2007 is a date that will always stand out to CJ’s mom, Sylvie Boucher. Boucher’s world changed forever that day – her birthday – when she learned her son had a brain tumour. But she doesn’t look back on that birthday with sadness. “It was my most beautiful birthday, because he’s still here today.”

The research was funded by the C17 Research Network, Genome Canada, b.r.a.i.n.child and SickKids Foundation.