The Role of Surgery for Malignant Glioma – Is it all good?

The Role of Surgery for Malignant Glioma – Is it all good?

Surgery has an important role in the diagnosis and treatment of patients with most brain tumours, including glioma patients with a suspected brain tumour are usually referred straight to a neurosurgeon for that reason. Traditionally, brain tumour surgery has been a core activity and skill for neurosurgeons, but better outcomes for almost all patients with brain tumours (especially gliomas/GBM/malignant glioma) are achieved when the patient is managed by a neurosurgeon with a subspecialty interest and training in neuro-oncology and at an institution with a brain tumour nurse coordinator and a skilled multidisciplinary team.

What does surgery do then, and how is it of benefit to the patient? These are questions worth reviewing periodically as the situation does evolve over the years for most cancers. Currently, for patients with suspected malignant gliomas, the role of surgery is to:

1. Provide tumour tissue for an accurate diagnosis 

This is even more important these days. Not only is it important to establish the histological diagnosis, but more and more the molecular and chromosomal signature of a given tumour is critical in predicting prognosis and dictating the appropriate treatment for the individual patient. It is also very important that specimens are available for research purposes, as future advances are dependent on this. Specimens for research can only be obtained by surgery, whether this by biopsy or by resection of the tumour mass.

2.Relief of symptoms

When a large brain tumour is present, it is often the cause of significant morbidity and potential mortality for a patient. Removing the mass, if it is possible, will usually help the patient immediately by reducing the effect of raised intracranial pressure, and often will improve neurological deficits and reduce the incidence of seizures.

3. Improved survival

It has always been somewhat controversial as to whether surgical resection actually improves survival in patients with malignant glioma/ GBM/ glioblastoma. There has only ever been one small randomised study comparing survival in patients undergoing resection versus biopsy, and resection proved to be better. Suffice to say however, the bulk of the evidence supports the contention that surgical resection will result in better survival than biopsy alone, as well as providing benefits as discussed above.

Surgical resection also poses more risk to the patient however, and therefore to maximise safety, my belief is that this surgery should be done by neurosurgeons with subspecialist training and in centres that can provide the appropriate and comprehensive peri- and postoperative care.

A recent study in a mouse model has also shown that surgical resection improves survival (Okolie et al, Neuro-Oncology, December 2016). But this study also showed that surgical resection can actually create a more aggressive tumour!

This is very important data as it implies that the trauma of surgical resection on the brain and the reactive changes in the normal brain cells around the surgical cavity can actually increase the growth rate and invasiveness of the glioma cells themselves.

The study also points to possible treatments that have not been considered in the past, and this is perhaps the future lies.

Will there be a time when surgical resection will not be required? Maybe, but not for the foreseeable future. If it does come about that surgery is not required, then I might be out of a job – but I would be happy because maybe there would be an effective treatment for malignant glioma.

By Prof David Walker, Neurosurgeon