According to pilot studies, doctors can read the entire genetic code of childhood cancers. This information will help them improve their diagnosis, understand the growth process, and determine the best treatments.
Cambridge doctors used whole-genome sequencing to examine 36 children with cancer. The test revealed that four patients were incorrectly diagnosed and seven new treatment options were available.
With a complete readout of DNA from the cancer, clinicians were able to refine two of their prior diagnoses, learn more about the probable course of disease in eight children, as well as discover possible genetic reasons for two of these tumours.
Our goal was to show what whole-genome sequencing can do and to promote its utility," said Dr Patrick Tarpey. Tarpey is the lead scientist for solid cancer at the east Genomic Laboratory hub, which is based at Cambridge University Hospitals NHS foundation trust. It was not really in doubt that this would be of value locally in Cambridge.
The results will be presented at the National Cancer Research Institute festival on Monday.
NHS England has begun whole-genome sequencing of childhood cancers. The goal is to make the tests routine parts of healthcare. This approach was first introduced by the 100k genomes Project, which resulted in seven genomic laboratory hubs (or GLHs), which are located at hospitals across the country.
There were 23 types of tumours among the 36 children who were recruited. Each child was tested for cancer using standard methods. Doctors sent blood and tumour samples to confirm the diagnosis.
Comparing the entire genetic makeup of a tumor with that of healthy tissue can help identify mutations and possibly reveal genes that make it more susceptible to certain drugs. The process is complicated and takes a lot of time. It can also give you detailed information but it can take up to three months to interpret. This is in contrast to the days or weeks that are required for more specific cancer tests.
Tarpey stated that about three quarters of the gene variants identified in the study were found through whole-genome analysis, rather than standard cancer tests. He said that there are instances when the diagnosis is not clear and we were able to confirm it and identify the genetic mechanisms responsible.
Daniel was just 10 years old when he was diagnosed after numerous visits to A&E. He also had subsequent medical tests. Although his tumour looked similar to an adult kidney cancer, it was very difficult to diagnose. Daniel was diagnosed with a form of adult kidney cancer and had to have the organ removed. He also received three weeks of radiotherapy for secondary tumours.
Doctors used whole-genome sequencing as part of the pilot study to examine Daniels' cancer. They found that it was similar in appearance to Wilms tumor, which can be treated with radiotherapy and chemotherapy. Tarpey said that the diagnosis proved that the doctors had followed the right treatment. Catherine, Daniel's mother, stated that he is now able to play basketball, football and other sports.
Daniel was diagnosed with rare kidney cancer at the age of 10. Photograph by Matthew Cafferkey/Cambridge University Hospitals NHS Trust
Sheona Scales is the paediatric lead at Cancer Research UK. She said that children with cancer are often subject to grueling treatments, and that even if the treatment succeeds, side effects can last a lifetime.
It is crucial that we tailor treatments to each individual. Whole-genome sequencing is an excellent tool for doing this. Knowing more about the characteristics of child cancer can help doctors make informed decisions for their patients. This knowledge will help children with cancer have better outcomes, not only in terms of survival but also in quality of life.