Understanding Stereotatic Radiotherapy

I visited The National Centre for Stereotactic Radiosurgery in Sheffield to get some understanding about stereotactic radiotherapy as a treatment for secondary breast cancer.

Twenty-two years living in Yorkshire have taught me one thing - we are usually quite modest about our achievements (we don’t like to make a song and dance about things). So, having previously worked closely with colleagues at Sheffield Teaching Hospitals for seven years, I was surprised to know that one of only a small number of national centres for stereotactic radiosurgery (housing a Gamma Knife) was right under my nose in Sheffield. 

Radiosurgery is a  method of focussing multiple narrow beams of radiation, with a very high degree of accuracy. It is used to treat a small defined area (or areas) within the brain, using a machine often referred to as a ‘Gamma Knife’ (it’s not a knife in the conventional sense). The Gamma Knife  works by focusing beams of gamma radiation on the target area. It has the ability to treat a very tightly defined target area with minimal effect on any surrounding tissue. Gamma Knife surgery is a highly accurate and specialised treatment exclusively for brain metastases. The Sheffield team treat around 400 secondary cancer patients who have brain mets, a year; these patients come from as far afield as Northern Ireland and Wales. 

There are several treatments for brain metastases including surgery, steroid therapy, conventional radiotherapy and stereotactic surgery. Referral to the stereotactic radiosurgery team can be made for any patients across the UK, by their oncologist as long as three criteria are met: Patients must have a life expectancy of greater than six months, systemic treatment options available and a performance status of 0-1. They must be referred with an up- to-date MRI scan with contrast performed within the last 4-6 weeks. Tumours up to 3cm large can be treated. A patient with a large number of lesions may find their treatment spread over a number of sessions.

Esther Buckland is the Superintendent Radiographer at Sheffield Teaching Hospitals and rightly prides herself on the level of care and support offered to her patients. Patients have a single staff member to look after them on the day of their treatment, help with transport, telephone aftercare advice line; even patient accommodation is available for those who might need it. For such a big and busy hospital (The Hallamshire) housing the Gamma Knife, the treatment and waiting areas are surprisingly calm, with lovely artwork by local artist Pete McKee to enhance the experience. 

Esther walked me through what happens to a patient during a consultation. Typically treatment happens quickly with an MDT to consider a patient’s case taking place seven days from referral; the trip to the clinic within a further seven days. Prior to a visit for treatment, a consultant neurosurgeon gives the patient the information needed about treatment. In terms of pre-assessment a patient will then meet with a therapeutic radiographer who will explain what will happen during treatment and complete any necessary screening (such as blood tests). Some radiosurgery patients are prescribed a short course of Dexamethasone (steroid) and an antacid. Another radiographer will then conduct a short pre-assessment examination to understand the patient’s general health, medications they may be taking and any specific requirements needed to be in place for radiosurgery.

On treatment day, a member of staff will fit the head frame needed for treatment. They will then be taken to the MRI scanner to have images taken. The next step is for a treatment plan to be created - this may take a couple of hours. When the plan is completed, the radiographers will carry out the treatment; actual treatment time can range from 20 minutes to several hours depending on the number of lesions to be treated.

The treatment will be similar to having any other scan. You will lie on a couch , listen to music and will feel no pain. Side effects in the medium term depend upon where the lesions are and their size. There is a small risk of swelling or reaction in the brain (less than 5% chance of this happening). Such reaction or swelling may cause symptoms which may include blurring of vision, weakness/numbness in a limb. If these symptoms become problematic a cortico-steroid may be advised.

Apart from the effects of local anaesthetic used for the frame application, there are few immediate side effects, maybe a headache by the end of a long day of treatment. The risk of seizures will have been discussed during the outpatient consultation).

Due to its highly focussed nature, radiosurgery is generally effective at controlling the local disease being treated however because it is so focussed it will not affect cancer elsewhere in the body.

Stereotactic radiosurgery and treatment with Gamma Knife are not suitable options for everyone but if you’d like to know more, visit https://www.gammaknife.org.uk/

Thanks to Esther Buckland, Julian Cahill and the rest of the team at The National Centre for Stereotactic Radiosurgery for their time.

Make 2nds Count is currently funding two research projects aimed at improving lives for those with brain metastases. HER2-CNS SURVEILLANCE Study and The PRIMROSE Studies can be found here.