What is Tumour Treating Fields?
Tumour Treating Fields (TTFields) is a cancer treatment approach that uses electric fields to disrupt cancer cell division and trigger cell death. Based on clinical trials so far, TTFields have been shown to improve prognosis for people with glioblastoma by several months.
Although available in many countries across the world, this medical device is not recommended by the National Institute for Health and Care Excellence (NICE) for newly diagnosed or recurrent glioblastoma and therefore is not available on the NHS in this country. NICE provide guidance and advice on improving health and social care, ensuring treatments and medicines used by the NHS are clinically beneficial and economical.
New health technologies to improve outcomes for UK brain tumour patients aren’t being made available as quickly as the urgent need demands.
How do TTFields work?
In normal cells, cell division (growth) is a tightly controlled sequence of events with a maximum number of divisions per cell. Cancerous cells, however, divide rapidly and uncontrollably leading to a mass of cells, forming a tumour that grows in size.
TTFields exploits this rapid cell division by delivering alternating electric fields to the mass of cells to disrupt the mechanisms involved in cell division, halting the process and causing cell death.
In experiments in the lab, TTFields have also been shown to:
- Alter the internal scaffolding of cells, disrupting their ability to migrate away from the main tumour site to new locations
- Activate the immune system to generate an antitumour response, and
- Reduce the activity of the genes responsible for DNA damage repair, resulting in cell death.
What does the treatment involve?
The most widely used clinical TTFields delivery system for glioblastoma patients consists of "transducer arrays", a field generator and a power source, which can be carried in a backpack or shoulder bag.
The arrays are attached in pairs at right angles directly to the patient’s shaved scalp. Each array is made up of ceramic discs through which the field generator delivers alternating electric fields across the brain and to the tumour site.
The device must be worn for several hours a day and can be used alongside the current standard of care for glioblastomas in the UK, which is surgery followed by chemotherapy (temozolomide - TMZ).
What are the treatment outcomes for TTFields?
Based on clinical trial data so far, the addition of TTFields to TMZ treatment, can extend survival by several months.
Published in JAMA in 2017, clinical trial results demonstrated a median overall survival (from trial start) of 20.9 months for those in the TTFields + TMZ treatment group, compared to 16.0 months in the TMZ only group.
The median progression-free survival (from trial start) was 6.7 months in the TTFields + TMZ group, compared to 4.0 months in the TMZ only group.
There are two clinical trials in the UK now looking at the best way to use TTFields in combination with other treatment options.
Who can potentially benefit?
Adults aged 18 year or older, with newly diagnosed glioblastoma (following surgery and radiotherapy, to be used alongside TMZ) or recurrent glioblastoma.
Are there any side effects from the treatment?
TTFields treatment has not been linked to significant system-wide side effects. The most common side reported at present is skin irritation beneath the arrays, which can vary in severity.
In addition, carrying the backpack with the power source and field generator in, is a consideration.
Are TTFields available to patients on the NHS?
No, TTFields is only available privately in the UK, funded either through self-pay or health insurance. It is very expensive, costing thousands of pounds per month. Some patients can also access the device via a clinical trial.
When will this device be available on the NHS?
For a medical device or medicine to be available on the NHS in England and Wales, it needs to be approved by NICE. Similar systems exist in Scotland and Northern Ireland. TTFields is not recommended by the National Institute for Health and Care Excellence (NICE) for newly diagnosed or recurrent glioblastoma. The technology has recently been discussed at NICE's prioritisation board, but there has not been enough new evidence, or a reduction in cost, that would affect its recommendation. They will continue to monitor ongoing trials investigating TTFields and will assess additional evidence when it becomes available.
More information on TTFields in the UK can be found here.