Why whole genome sequencing can improve child cancer treatments
Decoding the entire genetic sequence of a child's cancer should become standard practice in the NHS.
That's according to researchers who found it improved care in many cases - and provided more benefits than current tests.
Doctors studied the whole genome sequence of cancers in 281 children. In nearly a third of cases, it provided additional information about their illness and future treatment.
For 20 children, it improved decisions about their care that couldn't have been made without "gold standard" whole genome sequencing.
Some kind of genetic testing is performed on most cancer types and looks for certain mutations in the DNA of tumour cells (or blood cells in the case of blood cancers).
This can have a direct impact on how well the cancer might respond to treatments such as chemotherapy or radiotherapy.
But the genetic features of a cancer are particularly important in children - and multiple tests are often performed during a child's treatment.
A whole genome sequence test looks at all the mutations that might be present in a tumour or blood cancer cell and includes the "normal" genetic background of the individual, represented by genes unconnected to disease.
"Let's offer this to every child who walks through the door," said study author Professor Sam Behjati at the Wellcome Sanger Institute near Cambridge.
"This is a powerful example of the genomic data revolution of healthcare that enables us to provide better, individualised care for children with cancer."
Cambridge University Hospitals Trust and Great Ormond Street Hospital also took part in the study.
"In-depth genetic understanding of cancer is crucial in guiding our practice," said co-author Dr Jack Bartram at Great Ormond Street Hospital.
"Our research shows that whole genome sequencing delivers tangible benefits above existing tests."
One of the children in the study was Eddie Pessoa de Araujo, diagnosed with T-cell acute lymphoblastic leukaemia (T-ALL) when he was six.
Whole genome sequencing allowed Dr Bartram, who is also Eddie's consultant, to know his individual cancer was likely to respond well to standard chemotherapy treatment.
Eddie, now nine, has just completed treatment for T-ALL, which is now in remission.
"Having access to whole genome sequencing gave us some sense of reassurance, it could have informed us about targeted treatments and gave us some insight into future risk," said Eddie's mum Harri.
The whole genome of Eddie's cancer also revealed that his brother was not at increased risk of T-ALL.
Through its Genomic Medicine Service, NHS England already offers whole genome sequencing for any child diagnosed with cancer, but it's not routinely used by most hospitals.
The researchers conclude that it should be, and not just because of improvements to patient care.
Collecting more genetic information on the harmful mutations - and the normal genetic background in which they occur - of child cancer patients in the NHS would represent an invaluable resource for research.
"The UK is poised to be leading the world in cancer genomics research in children," said Prof Behjati.
