Genetic changes may help to improve decision making for the treatment of the rare and aggressive form of childhood cancer rhabdomyosarcoma, according to a new international study led by researchers at the Institute of Cancer Research, London (ICR).

The study analysed the DNA from 641 patients with rhabdomyosarcoma – a rare and aggressive type of childhood cancer that resembles muscle tissue and mostly affects children.

According to ICR, less than 30% of children with this type of cancer who have relapsed and whose disease has spread will survive.

There are two main subtypes of rhabdomyosarcoma, including fusion gene-positive and fusion gene-negative, depending on the presence of a ‘fusion gene’.

Researchers found that, when looking at those with fusion-negative rhabdomyosarcoma, children whose tumours had faults in the genes MYOD1 and TP53 had significantly poorer response to treatment and worse survival outcomes.

The TP53 gene was found to be altered in 69 out of 515 children and was linked to worse survival outcomes. In addition, around half of the children whose cancers had TP53 mutations succumbed to their disease compared with one in four children with cancers that were not TP53 mutant.

This indicated that patients without this type of mutation had a better chance of survival, according to the researchers.

Mutations in the MYOD1 gene, found in one out of 515 children, were also linked to both worse outcomes and rapid progression of the disease.

The findings of the study suggest that children with these mutations may benefit from a more aggressive treatment.

“This international collaborative effort has linked specific genetic changes in cancers to the ways that children respond to treatment. It should help clinicians to treat children according to the particular features of their cancer and the risk they face of their cancer progressing,” said Paul Workman, chief executive of ICR.

“The findings have the potential to have a real impact not only on survival but also on quality of life, by picking out those children who need the most aggressive treatment, but also sparing others with lower-risk disease from the side effects of intensive interventions,” he added.