DOI: 10.1007/s00259-016-3494-2Pages: 373-381

The prognostic value of FET PET at radiotherapy planning in newly diagnosed glioblastoma

1. The Finsen Center, Rigshospitalet, Department of Radiation Biology

2. Center of Diagnostic Investigation, Rigshospitalet, Department of Clinical Physiology, Nuclear Medicine and PET

3. The Finsen Center, Rigshospitalet, Department of Oncology

4. The Finsen Center, Rigshospitalet, Section of Radiotherapy

5. University of Copenhagen, Hvidovre Hospital, Laboratory of Gastroenterology

6. Center of Diagnostic Investigation, Rigshospitalet, Department of Radiology

Correspondence to:
Sidsel Højklint Poulsen
Tel: (+45) 35 45 63 27
Email: sidsel.hoejklint.poulsen@regionh.dk

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Abstract

Background

Glioblastoma patients show a great variability in progression free survival (PFS) and overall survival (OS). To gain additional pretherapeutic information, we explored the potential of O-(2-18F-fluoroethyl)-L-tyrosine (FET) PET as an independent prognostic biomarker.

Methods

We retrospectively analyzed 146 consecutively treated, newly diagnosed glioblastoma patients. All patients were treated with temozolomide and radiation therapy (RT). CT/MR and FET PET scans were obtained postoperatively for RT planning. We used Cox proportional hazards models with OS and PFS as endpoints, to test the prognostic value of FET PET biological tumor volume (BTV).

Results

Median follow-up time was 14 months, and median OS and PFS were 16.5 and 6.5 months, respectively. In the multivariate analysis, increasing BTV (HR = 1.17, P < 0.001), poor performance status (HR = 2.35, P < 0.001), O(6)-methylguanine-DNA methyltransferase protein status (HR = 1.61, P = 0.024) and higher age (HR = 1.32, P = 0.013) were independent prognostic factors of poor OS. For poor PFS, only increasing BTV (HR = 1.18; P = 0.002) was prognostic. A prognostic index for OS was created based on the identified prognostic factors.

Conclusion

Large BTV on FET PET is an independent prognostic factor of poor OS and PFS in glioblastoma patients. With the introduction of FET PET, we obtain a prognostic index that can help in glioblastoma treatment planning.

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  • Accepted: Aug 10, 2016
  • Online: Aug 23, 2016

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