TTF is a relatively new, non-invasive technique for adults with a type of brain tumour called a glioblastoma. It uses alternating electrical fields to disrupt tumour cell division, or cause cell death, thereby preventing the tumour from growing or spreading so quickly.
Using TTF involves a set of adhesive patches or bandages that hold insulated ceramic discs, called 'transducer arrays', onto your shaved head, forming what looks like a skull cap. The arrays are attached by wires to a portable battery-powered device that is carried in a shoulder bag or backpack.
The battery-powered device, also known as Optune® and which can alternatively be attached to a static power supply, creates alternating electrical fields, called Tumour Treating Fields or TTF. These fields are low intensity and disrupt the cell division process in rapidly dividing cells, such as tumour cells. The TTF are applied at a frequency which specifically targets glioblastoma cells. Normal adult brain cells divide slowly, if at all, so are thought not to be affected by TTF.
To get the best response to treatment, Optune® has to be worn continuously, and for at least 18 hours per day. This is because, unlike a drug, the effects of TTF on glioblastoma cells are only expected to occur when treatment is active. The total length of treatment will be determined by the doctor.
The arrays have to be changed, and the scalp re-shaved, one to two times per week, to make sure a good contact is maintained with the skull.
There have been some clinical trials of Optune® in newly diagnosed and recurrent glioblastoma. The results show prolonged survival in newly diagnosed patients with glioblastoma treated alongside temozolomide (TMZ). These patients have a 5-year survival rate of 13% compared to control patients, not using Optune®, of 5%.
The average (median) overall survival, from the start of treatment, was 20.9 months in patients treated with Optune® plus TMZ, compared to 16 months in patients treated with TMZ only.
The Optune® device is FDA (Food & Drug Administration) approved in the USA; and CE marked in the European Union. This means it has proved itself to be "safe and effective" in the US, and fits the essential requirements for health and safety in the EU.
Novocure, the company that produces Optune®, is hoping, in the future, to get the treatment through a review by NICE (National Institute for Health and Care Excellence) in the UK. (NICE provides guidance and sets quality standards for health, public health and social care.)
The most common side-effects are mild to moderate skin irritation on the scalp and headaches. When used with chemotherapy, low blood platelet count, nausea, constipation, vomiting, tiredness, seizure, and depression. Other side-effects, that may be due to using the device, include muscle-twitching, skin ulcers and malaise (general feeling of being unwell).
Optune® is currently not available through the NHS. Patients with the necessary insurance cover, or the ability to cover at least a substantial part of the treatment cost, can ask their doctor to contact Novocure. In June 2017 the treatment costs were €21,000 per month (over £18,000 per month).
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