For the first time, the 2016 classification uses molecular information to establish a brain tumour diagnoses. This information will enable a more precise evaluation of a tumour type and will have significant repercussions for the treatment and study of brain and CNS tumours.
To date, giving an accurate diagnosis of tumour type a pathologist would take a sample of the tumour, analyse it in a laboratory and classify it in accordance with the WHO classification. There are currently over 136 classifications of brain tumour subtypes distinguished by grade, the type of cell they grow from and position in the brain.
The new WHO classifications expand the number of genetic subtypes of tumour to reflect improved knowledge of the biological characteristics of tumours. This will enable clinicians to undertake a more specific analysis of the tumour with a wider variety of tests.
According to co-author of the WHO publication, Professor Peter Collins: “These new classifications and findings will have a dramatic impact on how we diagnose brain tumours and the treatment options available.
“Previously we have diagnosed the type of tumour by looking at the appearance of the tumour cells in thin sections of the tumour through a microscope (histopathology) after they have been stained with various dyes.
“However since finding new biomarkers, that are unique to certain tumour types, we will now additionally be assessing many of the tumours at a molecular level.
“These biomarkers will have significant impact upon patients. Firstly, we should be able to give a more accurate diagnosis and prognosis. Secondly, it will mean in some cases we will be able to predict how tumours will react to treatments based on the molecular changes present in the tumour cells, and can choose treatment accordingly. Thirdly, it should lead to the production of new, more specific, therapies based on the tumour cell biology."
The development of targeted treatments based on tumour cell biology may improve survival and reduce aggressive side effects, so accurate diagnosis is crucial. The Brain Tumour Charity has funded research into targeted treatments.
It is important that resource and time is given to enable clinicians to take advantage of the new classifications.
However, we welcome the changes to the classifications which are a step forward and will make a significant contribution to the development and delivery of new treatments to double survival and half the harm.