A special radiotherapy treatment for brain tumours, hailed as a miracle cure by the British press, is far from that, say two leading specialists.
The risk of radiation damage can be as high as 50 per cent, visual impairment occurs in 24 per cent of cases and 30 per cent of patients suffer lobe damage.
The technique, known as gamma knife because of its high precision irradiation to a central target, has been championed by the media because it can treat ‘many potentially fatal brain conditions which are inoperable’.
But this type of publicity is misleading and offers false hope, say Michael Brada, a senior lecturer in clinical oncology at the Institute of Cancer Research, and Garth Cruickshank, professor of neurosurgery at Queen Elizabeth Hospital in Birmingham.
Although gamma knife treatment has been used for 30 years, there has never been a randomised, controlled study to test its efficacy and safety.
Most favourable reports have come from cases of radiosurgery to patients with small brain tumours, but the evidence that exists does not bear out this enthusiasm. The rate of subsequent haemorrhage within two years of treatment is around 8 per cent, while the risk of radiation induced damage is up to 30 per cent for a 2 cm diameter lesion, and 50 per cent for a 3 cm one.
Radiosurgery has been advocated for people with benign tumours, but the recurrence rate at five years is more than 10 per cent, while visual impairment has been reported in 3.4 per cent and 24 per cent of patients in several studies. Over 30 per cent developed temporal lobe damage (BMJ, 1999; 318: 411-2).