Gliomas and Glioblastoma Multiforme

See related articles on Space Occupying Lesion, Brain Tumours in Children and Brain Tumours in Adults.

Gliomas are tumours arising from glial cells and may occur in the spinal cord or the brain, the latter being more common.

There are four broad groups of gliomas, based on which cells they resemble:

1. Ependymomas (ependymal cells)
2. Astrocytomas (astrocytes) of which glioblastoma multiforme is the commonest
3. Oligodendrogliomas (oligodendrocytes)
4. Mixed gliomas e.g. oligoastrocytomas

Gliomas can also be classified according to their grade and/or location e.g. supra and infratentorial.

Neuroglial tumours account for 80% of primary brain tumours.¹ Glioblastoma multiforme is the commonest glioma to occur in adults being diagnosed at the age of 55 years on average. Low grade astrocytomas tend to be seen in younger adults aged 20-30 and anaplastic astrocytomas typically present in the mid-forties, which is similar to oligodendrogliomas.

This is as a space occupying lesion. Presentation will also depend upon location. The following are some features that might be seen:

• Headache - typically worse on waking
• Nausea and vomiting
• Seizures - especially low grade astrocytomas
• Intracranial bleeding - may rarely occur in association with glioblastoma multiforme

• Involves brain imaging e.g. CT scan and/or MRI scan with or without contrast. Glioblastoma multiforme typically has ring enhancement.
• Tissue specimens for pathology are usually required (if possible to obtain) as there is a large variety of tumours that may occur.²
• Tissue may also be examined for chromosomal analysis.

There is no standard staging system for brain tumours. Brain tumours can spread to other parts of the brain and the spinal cord - but distant metastases are rare.

• This involves a combination of surgery, radiotherapy and chemotherapy.
• Surgery is performed, if feasible depending on the location and grade of the tumour.
• Radiotherapy may be external or internal beam radiation. External beam is the commonest and may be delivered as standard external beam or stereotactic.
• Photodynamic therapy involves targeting lesions with a laser after rendering them light sensitive. It is currently being evaluated by NICE.^3,4

Treatment of specific tumours

Grade 1 and 2 tumours

• This includes pilocytic astrocytomas, pleomorphic xanthroastrocytomas and subependymomas.
• They can be cured by complete resection.
• Incompletely resected tumours may not cause any problems or can be treated further with radiation which will lead to a cure.
• If these measures fail then rarely chemotherapy may help.

• Maximum possible surgical debulking.
• Radiation therapy is standard.
• Adjuvant chemotherapy has been used in trials but its role needs to be clearly established e.g. bevacizumab and irinotecan.⁵
• However, recurrence after radiotherapy should be treated with chemotherapy.
• NICE advises carmustine implants in patient with newly diagnosed high-grade glioma if 90% or more of the tumour has been removed.⁶

• Surgery is the mainstay of therapy - but the tumour is usually infiltrative and thus complete resection is difficult.
• Radiotherapy increases survival.
• Concomitant and adjuvant chemotherapy with temozolomide given during and after radiotherapy improves survival.^6,7
• Recurrence can be treated with a second resection if possible and/or further chemotherapy with temozolomide.

• Surgical resection and radiotherapy are the mainstays of treatment.⁸
• Chromosomal analysis has revealed that oligodendrogliomas with loss of 1p19q respond well to chemotherapy and radiotherapy.¹
• Procarbazine and vincristine are amongst the agents that are used.

Gliomas are associated with a poor prognosis especially the high grade types and in older patients. Survival rates of approximately 30% at one year and 14% at two years have been reported.⁹ High grade tumours have a better outcome if complete resection is achieved.

There has been a recent decline in 5 year survival (up until the late 1990s) - especially in males. This is an interesting feature as in England and Wales the trend has been for cancer survival rates to increase.⁹

Low grade astrocytomas can, rarely, recur and thus patients must be followed up for at least 15 years.