How Can Radiotherapy Treat Different Glioma Types?

Gliomas are brain tumours that arise in the glial cells, located in the brain and spinal cord. They are malignant (cancerous) and come in various categories, which, when put together, account for around 80 per cent of brain tumours.

Here, we explore what the various tumours are, as well as how they can be treated, with a particular focus on the use of stereotactic radiotherapy, a method of delivering radiation very precisely to a tumour to shrink it while minimising exposure for surrounding healthy brain tissue.

With this knowledge, you will be in a better position to understand the glioma treatment options open to you and be aware of what we are able to offer.

The Diagnosis And Classification Of Gliomas

The function of glial cells is to assist the workings of the central nervous system. However, they are the most common place for brain and spinal cord tumours to begin.

Often, their emergence can lead to pressure being placed on the brain, which can impede certain functions. Depending on where the tumour is located, symptoms could include emerging problems with speech, motor movement or eyesight, among other functions. Diagnosis involves MRI scans and, sometimes, a biopsy.

However, different kinds of tumour can grow at varied rates, with the more aggressive, fast-growing ones being graded higher on a system that ranks them from one to four. Grade four gliomas are the fastest-growing and grade one gliomas are the slowest.

For example, glioblastomas are grade four, while astrocytomas come in different forms and can be anywhere from one to four. The grading factors will have different implications for patients, not least the type of treatment options that may be best suited in each case.

Glioma Types

Oligodendrogliomas are a slightly different case, as they can only be grade two (less aggressive) or the more aggressive grade three types.

A defining characteristic of them is that they form in a specific kind of cell called oligodendrocytes, which have the basic function of covering and insulating nerve cells. These tumours are usually found in the brain and only rarely in the spinal cord.

Astrocytomas also arise in a specific type of cell, known as astrocytes. As the ‘astro’ part of the name suggests, these are star-shaped. Although they can affect people in different age groups, it is usually the case that low-grade astrocytomas are more common in children, while higher grades are seen in adults.

Glioblastomas also begin in the astrocytes and are the most aggressive, although the spread is usually confined to the brain and spinal cord. They are usually found in patients aged over 45.

Treatment Options

Treatments for these brain tumours include surgery, chemotherapy and radiotherapy. While the more urgent and aggressive interventions will be more imperative for higher-grade tumours, a range of factors will determine the range of viable treatment options.

Radiotherapy may or may not be used in combination with other treatments, which can depend on various factors such as the size and location of the tumour.

For example, surgery may be used to cut out part or all of a tumour if it is easily accessible. In such cases, radiotherapy can help to impede the regrowth of tumour tissue, shrinking it and preventing effects such as the tumour pressing on the brain and hampering various functions.

In some cases, the tumour location makes physical surgery unsafe and radiotherapy must proceed without this. However, in either case, the form of radiotherapy we use is stereotactic radiotherapy.

This is designed to deliver intense, powerful beams of radiation to a very specific location while minimising exposure for the surrounding tissue. This is used whenever the adjacent organs are essential, which is especially the case with the brain. Minimising exposure to radiation in healthy tissue reduces the side effects of treatment.

The Role Of Gamma Knife

Gamma Knife stereotactic radiosurgery is considered only for carefully selected, small, well-defined targets (such as recurrence or focal boost), or when anatomy makes open surgery and conventional radiotherapy boosts less suitable.

The device by which stereotactic radiotherapy is best delivered is Gamma Knife, which, despite its name, involves no physically invasive action. This device was invented by Swedish neuroscientist Lars Leksell in the 1960s, with more advanced versions being developed over time.

However, the key working element of the device is the gamma radiation. These rays are ideal for directing radiation with very high levels of precision, which makes this device suitable for targeting very specific areas. That is why we use this for brain tumour treatment.

If you have recently been diagnosed, you may have many questions to ask. As part of our personalised care, we will tailor your treatment programme to your specific medical needs and keep you informed and involved with decisions at every stage.

Explore the Queen Square website to learn more about our advanced radiotherapy treatments for gliomas.