Study confirms side-effects of radiotherapy for low-grade glioma brain tumours
A new study has confirmed that patients who undergo radiotherapy for a type of brain tumour called a low-grade glioma (LGG) may experience a decline in their mental ability in later years.
LGGs are a particular type of brain tumour that tend to grow slowly and often cause few symptoms.
Patients with LGG brain tumours used to be treated with radiotherapy, but surgery has been the preferred form of treatment for a number of years after evidence showed it to be more effective in the early stages of the disease.
Now, a new study in the Lancet Neurology medical journal has lent support to this consensus, suggesting that even low doses of radiotherapy may contribute to mental decline in these patients.
Researchers at VU University Medical Centre in Amsterdam studied 65 patients, all of whom had a follow-up assessment of their mental skills around 12 years after treatment.
Approximately half of the study participants had been treated with radiotherapy when they were first diagnosed, while the others had never received radiation treatment.
The researchers found that 27 per cent of those who did not have radiotherapy showed signs of cognitive disability after 12 years, compared with 53 per cent of those who had received the treatment.
Radiotherapy patients tended to perform worse in a number of areas, including attention and information processing speed.
In contrast, the ability of patients who did not receive radiotherapy tended to be stable.
The authors wrote: "The current results indicate that radiotherapy is associated with long-term cognitive deterioration, regardless of fraction dose ... [and indicate that] all surviving patients who had radiotherapy are at risk of developing attentional problems."
Writing in an accompanying comment, Paul Brown and Jane Cerhan from the Mayo Clinic in Rochester, US, noted that the techniques used in modern radiotherapy are very different to those used during the study's treatment period.
Dr Jeremy Rees, a Cancer Research UK scientist at the National Hospital for Neurology and Neurosurgery, also pointed out that radiotherapy is rarely used to treat patients with LGG.
"We normally try to avoid giving radiotherapy to patients with low-grade glioma, unless the tumour is progressing or they have epilepsy not controlled on standard medication," he explained.
"Surgery is generally a preferred option with chemotherapy or radiotherapy coming into play at a later stage if the glioma progresses. Continued research and increased knowledge about the disease is enabling us to treat it increasingly effectively while reducing side effects."
Douw, L., Klein, M., Fagel, S., van den Heuvel, J., Taphoorn, M., Aaronson, N., Postma, T., Vandertop, W., Mooij, J., & Boerman, R. (2009). Cognitive and radiological effects of radiotherapy in patients with low-grade glioma: long-term follow-up The Lancet Neurology, 8 (9), 810-818 DOI: 10.1016/S1474-4422(09)70204-2