• Vol. 36 No. 5, 332–337
  • 15 May 2007

Optimising Radiation Therapy Techniques for Tumours of the Central Nervous System

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ABSTRACT

Introduction: This study aims to assess the early tumour outcome and morbidity associated with radiation therapy (RT) in tumours of the central nervous system (CNS). Materials and Methods: Patients receiving RT with radical intent were entered on a prospective database. Tumour types were categorised into glioma, base of skull, pituitary, germ cell or primitive neuroectodermal tumour (PNET) and other malignant CNS tumours. Study endpoints were overall survival and progression free survival. Acute and late toxicity endpoints included Common Terminology Criteria version 3.0 (CTC) grade 3 or 4 events, need for admission during RT and change in performance status at 12 months. Results: One hundred and fifty-two patients with CNS tumours were managed with radical intent over the 4-year period. The median age was 49 years and 68.4% were Eastern Co-operative Group (ECOG) 0-1 performance status. The major pathology groups were glioma (59.9%) and base of skull tumours (17.1%). Gross total resection was performed in 28.3% only and RT was delayed after diagnosis until time of progression in 19.7%. For the 91 patients with glioma, the median survival and 2-year survival rate was 19.1 months and 44.1%, respectively. The 2-year survival rates for the subgroups of WHO Grade I or II, III and IV were 100%, 52% and 35%, respectively. For the non-glioma tumour groups, the relapse varied with pathology. Toxicity was minimal with only 3 acute and 3 late CTC grade 3 or 4 events occurring. Overall, 47 or 31% of patients required some inpatient hospitalisation during RT, although this was determined to have some causative relationship to RT in only 12 or 8% of patients. In the 12 months post-RT, performance status was stable or improved in 76.2% of patients, and most deterioration was associated with tumour relapse. Conclusions: RT for CNS tumours using modern techniques was well-tolerated with good tumour outcome and minimal morbidity.


Tumours of the central nervous system (CNS) are a diverse group of pathologies with varying natural histories and outcomes. The presence of adjacent sensitive neural structures limits the role of surgery to achieve complete tumour excision; similarly, the blood-brain barrier restricts the penetration and activity of many systemic chemotherapy agents.1,2 Radiation therapy (RT) has a major role in the management of CNS tumours, as the ability of fractionated RT to destroy tumour cells but allow normal cell repair results in relative sparing of neural tissues. However, there are concerns regarding the effects of high-dose RT on neurocognitive function, cerebrovascular events and second malignancy.3 This is more relevant for tumours with a long natural history in which delayed morbidity from slow tumour progression is weighed against the potential early treatment-related toxicity.

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