Gliomas are the commonest primary, malignant tumour of the brain and account for more average years of life lost than all other cancers (Burnet NG et al Br J Cancer. 2005; 92(2):241-245). Glioblastomas are the commonest malignant tumour and encompass a spectrum of genetic subtypes characterised by rapid invasion causing deterioration in quality of life before death from progressive disease. Low grade gliomas comprise of a group of slow growing but malignant tumours that slowly progress before transforming into glioblastomas. Patients describe this as ‘living with a time-bomb in their brain”. The lack of new therapies makes optimising current treatments a priority.
Surgery plays a major role in managing gliomas – especially where adjuvant therapies are ineffective (Ewelt C et al, J Neurooncol. 2011; 103(3):611-618). Complete resection improves outcome and delays progression (Stummer W et al Acta Neurochir (Wien). 2011; 153(6):1211-1218.; Stummer W, et al Journal of Neuro-Oncology. 2012:1-9; Brown TJ et al. JAMA Oncol. 2016) if it is possible to identify all of the tumour (Roberts DW et al. J Neurosurg. 2011; 114(3):595-603). Radiotherapy is limited by the sensitivity of the brain to radiation induced injury – our lack of understanding the mechanisms and factors that determine normal tissue response (Burnet NG et al. Int.J.Cancer. 1998; 79(6):606-613) is a major limitation to improving radiotherapy delivery to optimise brain tumour control.
Brain injury from tumours is two-fold:
- Injury due to tumour invasion
- Injury caused by treatment of tumours
The impact of such an injury is not well understood. It impacts the quality of life and cognitive functioning, yet neuro-oncology research focuses on survival and fails to routinely record these outcome measures.