Effect of radiotherapy on brain glucose metabolism in patients operated on for low grade astrocytoma
- M Bruehlmeiera,
- U Roelckea,
- B Amslerb,
- K H Schubertb,
- O Hausmannc,
- K von Ammone,
- E W Radüd,
- O Gratzlc,
- C Landmannb,
- K L Leendersa,f
- aPET Program, Paul Scherrer Institute, CH-5232 Villigen, Switzerland, bDepartment of Radiotherapy, cDepartment of Neurosurgery, dDepartment of Neuroradiology, University Hospital, CH-4031 Basel, Switzerland, eDepartment of Neurosurgery, fDepartment of Neurology, University Hospital, CH-8091 Zürich, Switzerland
- Dr M Bruehlmeier, PET Program, Paul Scherrer Institute, CH-5232 Villigen, Switzerland. Telephone 0041 56 310 36 84; fax 0041 56 310 31 32; email: Matthias.Bruehlmeier{at}psi.ch
- Received 30 December 1997
- Revised 6 August 1998
- Accepted 29 October 1998
Abstract
OBJECTIVE To assess the effect of postoperative radiotherapy on brain glucose metabolism (CMRGlu) of operated patients with low grade astrocytomas.
METHODS PET and18F-fluorodeoxyglucose was used to measure absolute CMRGlu in patients with fibrillary astrocytoma (WHO II) of the frontal lobe, who did (n=7) or did not (n=12) receive radiotherapy subsequent to first debulking tumour resection. In addition, statistical parametric mapping (SPM95) was applied to assess the pattern of relative CMRGlu associated with the frontal tumour. Data were compared with 12 healthy controls.
RESULTS A global reduction of absolute CMRGlu was found when either patients with or without radiotherapy were compared with controls (ROI analysis). Brain areas of relative CMRGlu reduction were found in the brain ipsilateral and contralateral to the tumour, comparing both patient groups with controls by SPM (“tumour diaschisis effect”). Superimposed, absolute CMRGlu in the contralateral frontal, parietal, occipital cortex as well as in the white matter was on average 17% lower in patients receiving radiotherapy than in patients who did not.
CONCLUSIONS The data discriminate a tumour effect from a radiotherapy effect, and support the view of adverse effects of radiotherapy on brain not directly involved by tumour.
