Use of 11C-methionine PET to monitor the effects of temozolomide chemotherapy in malignant gliomas

Eur J Nucl Med Mol Imaging. 2006 May;33(5):516-24. doi: 10.1007/s00259-005-0002-5. Epub 2006 Feb 1.


Purpose: The purpose of this study was to monitor the metabolic effects of temozolomide (TMZ) chemotherapy in malignant gliomas by means of repeated positron emission tomography (PET) with [(11)C]methionine (MET).

Methods: Fifteen patients with histologically proven malignant glioma were treated by TMZ chemotherapy. MET-PET studies were performed before and after the third cycle of TMZ chemotherapy in all patients, and in 12 patients also after the sixth cycle. Gadolinium-enhanced MRI studies were performed in 12 patients before the first and after the sixth cycle. Clinical status was assessed by the modified Rankin scale. Long-term outcome was assessed by calculating the time to progression (TTP) in months.

Results: Decline in MET uptake during therapy corresponded to a stable clinical status. The median TTP was significantly longer in patients with decline in MET uptake than in those with increasing MET uptake (23 vs 3.5 months; p=0.01, log rank test). There was no significant correlation between change in MET uptake and change in contrast enhancement during treatment for all patients.

Conclusion: The present data demonstrate that clinical stability, which is often achieved under TMZ chemotherapy of malignant glioma, corresponds to a decline in or stability of tumour amino acid metabolism. Tumour responses can already be demonstrated with MET-PET after three cycles of chemotherapy, and absence of progression at that time indicates a high probability of further stability during the next three cycles. A reduction in MET uptake during TMZ treatment predicts a favourable clinical outcome. Molecular imaging of amino acid uptake by MET-PET offers a new method of measurement of the biological activity of recurrent glioma.

Publication types

  • Clinical Trial

MeSH terms

  • Adult
  • Aged
  • Antineoplastic Agents, Alkylating / therapeutic use
  • Dacarbazine / analogs & derivatives*
  • Dacarbazine / therapeutic use
  • Female
  • Glioma / diagnostic imaging*
  • Glioma / drug therapy*
  • Humans
  • Male
  • Methionine*
  • Middle Aged
  • Positron-Emission Tomography / methods*
  • Prognosis
  • Radiopharmaceuticals
  • Reproducibility of Results
  • Sensitivity and Specificity
  • Temozolomide
  • Treatment Outcome


  • Antineoplastic Agents, Alkylating
  • Radiopharmaceuticals
  • carbon-11 methionine
  • Dacarbazine
  • Methionine
  • Temozolomide