Stereotactic Radiosurgery (SRS)

Stereotactic radiosurgery (SRS), involves the delivery of a high dose of focused radiation therapy to a small area in the brain or other parts of the head. This is usually delivered in one, or sometimes up to 5 treatment sessions. When one treatment is used it is termed SRS and if more than one treatment is used it is termed stereotactic radiation therapy (SRT).

Although it has the word surgery in the name, it does not involve any surgical cuts and is a non-invasive treatment for patients with tumours or cancers of the brain and head region.

SRS is commonly used to treat patients with:

. secondary cancers that have spread to the brain (brain metastasis)

. secondary cancers after they have been resected

. slow growing benign tumours (such as acoustic neuromas, meningiomas and pituitary tumours)

. re-treat an area that has previously had radiation therapy before

. non-tumour conditions such as arteriovenous malformations (abnormal connection of veins and arteries) and complex cases of trigeminal neuralgia. Trigeminal neuralgia is facial pain caused by pressure or damage to the 5th cranial nerve and can occur as part of some neurological conditions like multiple sclerosis.

There is a large expert team involved in planning and delivering SRS including specialist radiation oncologists, radiation therapists, medical physicists and nurses. Usually patients are discussed in a multi-disciplinary meeting involving radiation oncologists, surgeons, medical oncologists, neurologists and radiologists before treatment. It is not suitable for all patients, as many factors need to be carefully considered before treatment is recommended. The overall condition of the patient, current symptoms, and the areas involved are some of the many factors that are assessed before treatment.

Delivery of stereotactic radiosurgery

There are different ways of giving SRS, (e.g. Linear Accelerator Based, GammaKnife, Cyberknife, Tomotherapy) but all systems have the same key features in common. All systems deliver precise and safe radiation therapy with high accuracy to minimise the dose to healthy structures surrounding the tumour or cancer. To do this a fitted head frame or mask may be used to minimise any movement, ensuring that the patient is comfortable at all times. X-rays may be taken to ensure that the patient is positioned accurately with measurements taken before the treatment is given. Depending on the type of SRS and number of areas receiving SRS, set-up and treatment generally takes between 30 minutes to 1 hour in total.

Delivery of SRS is not painful. It is usually well tolerated by patients. The potential side effects of treatment vary depending on the area being treated. These will be discussed by the treating radiation oncologist. Some people may get side-effects following treatment including tiredness, mild nausea or headache. These are usually only temporary and mild in nature. Other rarer side-effects may occur months or years after treatment but are not common. The meticulous planning and treatment processes used in SRS minimise these side-effects.

The expected results of treatment vary according to the condition being treated and cannot therefore be easily summarised.  Your radiation oncologist will give you many more details about this and all aspects of the SRS process before a final decision is made about treatment with this special technique.

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