Nineteen-year-old Ben Ho was at the cusp of a new life – he was a month away from joining the National University of Singapore (NUS) – when he was struck by shattering news: he had leukaemia. Overnight, Ben, who had been looking forward to the challenges of student life, was facing far graver challenges. But help was at hand and on campus. Through family friends, Ben met paediatric cancer specialist Associate Professor Allen Yeoh from the NUS Yong Loo Lin School of Medicine (YLLSoM). A/Prof Yeoh, who is one of the brains behind the National University Hospital’s (NUH) 85 percent cure rate for childhood leukaemia, took on Ben as his first adult patient. NUH is the principal teaching hospital of YLLSoM. A/Prof Yeoh is Senior Consultant at University Children’s Medical Institute’s Division of Paediatric Haematology-Oncology at the NUH.
This year, a healthy Ben graduated from NUS’ School of Design and Environment, one of Prof Yeoh and his team’s many success stories.
Compared with cure rates outside Singapore, which range from less than 10 percent in Vietnam to up to 60 percent in some of the best hospitals in India, NUH’s 85 percent cure rate rivals the best hospitals worldwide. Prof Yeoh, whose area of speciality is Acute Lymphoblastic Leukaemia (ALL), the most common type of children’s cancer, and Acute Myloid Leukaemia, describes his success strategy as “doing more with less”.
Prof Yeoh says, “We can improve treatment by giving the optimal intensity of therapy; for the majority of patients this means less treatment.” Instead of treating patients with a uniform dose of chemotherapy, which comes with long-term side effects, he tailors the treatment to the severity of the disease. With the help of molecular markers developed by his team, he is able to detect, after initial treatment, the presence of up to one leukaemia cell in 10,000 normal cells. Previously, conventional microscopes could only identify five leukaemia cells among 100 normal cells. With this minimal residual disease (MRD) methodology, the team is able to predict the risk of relapse and deliver the optimal intensity of treatment required. “For those with less than one in 10,000 normal cells after the first month of therapy, the survival rate is 90 percent and their treatment can be decelerated while maintaining the high cure rate,” says Prof Yeoh. For those with a poorer prognosis, Prof Yeoh intensifies chemotherapy, wich has doubled the cure rate for this high-risk segment of patients as well.
Prof Yeoh says that the department’s success has depended to a great extent on the support of organisations like the Lee Foundation, Children’s Cancer Foundation and Viva Foundation, whose seed funding allowed him to, as he says, “catch the winds” of progress in biomedical research in Singapore. Philanthropic funding such as these enabled him to build infrastructure and manpower, which is crucial to monitoring patients over the years and building data for his research. The Lee Foundation and Children’s Cancer Foundation also support the annual St Jude-Viva Forum in Paediatric Oncology, which brings together world leaders in the field to share the latest information and disseminate findings. The Forum is organised by the Viva Foundation for Children with Cancer, St Jude Children’s Research Hospital in the US, NUS and NUH.
Prof Yeoh and YLLSoM have long been at the vanguard of paediatric leukaemia treatment. His mentor, Prof Quah Thuan Chong, Department of Paediatrics, YLLSoM, was among the first in Asia to replace the traditional routine radiation therapy to the brain and testes, which affected children’s IQ and left males sterile, with high doses of chemotherapy. The cure rate jumped from 50 to 75 percent in trials that ran from 1988 to 1996. From 1997 to 2010, Prof Yeoh and his team collaborated on studies with hospitals in Hong Kong (1997-2002) and Malaysia (2003- to date), raising the cure rate to 80 percent.
Prof Yeoh also came up with the idea of using the gene chip, which “eavesdrops” on messages coming out of DNA to identify the various subtypes of ALL, allowing for further fine-tuning and customising of treatment. The utility of the gene chip, which was developed in collaboration with St Jude Children’s Research Hospital, won Prof Yeoh the American Society of Haematology Merit Award in 2001 and the Singapore Youth Award in 2003.
Currently, the team is looking to further improve cure rates for high-risk patients and increased customisation of treatment. They are currently working with National Medical Research Council (NMRC) STaR investigator, Prof Dario Campana from Yong Loo Lin School of Medicine on engineering natural killer cells in the body to destroy cancer cells. Natural killer cells are our body’s first line of defence against cancer. Prof Campana’s laboratory can re-engineer natural killer cells to seek out the residual cancer cells and destroy them. The prestigious STaR Investigator Award is jointly offered by NMRC and the Agency for Science, Technology and Research (A*STAR) to recognise and support investigators with outstanding qualifications in translational and clinical research.