Universität zu Köln

Piroth, Marc D., Galldiks, Norbert ORCID: 0000-0002-2485-1796, Pinkawa, Michael, Holy, Richard, Stoffels, Gabriele ORCID: 0000-0001-7114-1941, Ermert, Johannes ORCID: 0000-0002-2561-7766, Mottaghy, Felix M., Shah, N. Jon ORCID: 0000-0002-8151-6169, Langen, Karl-Josef ORCID: 0000-0003-1101-5075 and Eble, Michael J. (2016). Relapse patterns after radiochemotherapy of glioblastoma with FET PET-guided boost irradiation and simulation to optimize radiation target volume. Radiat. Oncol., 11. LONDON: BMC. ISSN 1748-717X

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Abstract

Background: O-(2-18 F-fluoroethyl)-L-tyrosine-(FET)-PET may be helpful to improve the definition of radiation target volumes in glioblastomas compared with MRI. We analyzed the relapse patterns in FET-PET after a FET- and MRI-based integrated-boost intensity-modulated radiotherapy (IMRT) of glioblastomas to perform an optimized target volume definition. Methods: A relapse pattern analysis was performed in 13 glioblastoma patients treated with radiochemotherapy within a prospective phase-II-study between 2008 and 2009. Radiotherapy was performed as an integrated-boost intensity-modulated radiotherapy (IB-IMRT). The prescribed dose was 72 Gy for the boost target volume, based on baseline FET-PET (FET-1) and 60 Gy for the MRI-based (MRI-1) standard target volume. The single doses were 2.4 and 2.0 Gy, respectively. Location and volume of recurrent tumors in FET-2 and MRI-2 were analyzed related to initial tumor, detected in baseline FET-1. Variable target volumes were created theoretically based on FET-1 to optimally cover recurrent tumor. Results: The tumor volume overlap in FET and MRI was poor both at baseline (median 12 %; range 0-32) and at time of recurrence (13 %; 0-100). Recurrent tumor volume in FET-2 was localized to 39 % (12-91) in the initial tumor volume (FET-1). Over the time a shrinking (mean 12 (5-26) ml) and shifting (mean 6 (1-10 mm) of the resection cavity was seen. A simulated target volume based on active tumor in FET-1 with an additional safety margin of 7 mm around the FET-1 volume covered recurrent FET tumor volume (FET-2) significantly better than a corresponding target volume based on contrast enhancement in MRI-1 with a same safety margin of 7 mm (100 % (54-100) versus 85 % (0-100); p < 0.01). A simulated planning target volume (PTV), based on FET-1 and additional 7 mm margin plus 5 mm margin for setup-uncertainties was significantly smaller than the conventional, MR-based PTV applied in this study (median 160 (112-297) ml versus 231 (117-386) ml, p < 0.001). Conclusions: In this small study recurrent tumor volume in FET-PET (FET-2) overlapped only to one third with the boost target volume, based on FET-1. The shrinking and shifting of the resection cavity may have an influence considering the limited overlap of initial and relapse tumor volume. A simulated target volume, based on FET-1 with 7 mm margin covered 100 % of relapse volume in median and led to a significantly reduced PTV, compared to MRI-based PTVs. This approach may achieve similar therapeutic efficacy but lower side effects offering a broader window to intensify concomitant systemic treatment focusing distant failures.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Piroth, Marc D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Galldiks, Norbert UNSPECIFIED orcid.org/0000-0002-2485-1796 UNSPECIFIED Pinkawa, Michael UNSPECIFIED UNSPECIFIED UNSPECIFIED Holy, Richard UNSPECIFIED UNSPECIFIED UNSPECIFIED Stoffels, Gabriele UNSPECIFIED orcid.org/0000-0001-7114-1941 UNSPECIFIED Ermert, Johannes UNSPECIFIED orcid.org/0000-0002-2561-7766 UNSPECIFIED Mottaghy, Felix M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Shah, N. Jon UNSPECIFIED orcid.org/0000-0002-8151-6169 UNSPECIFIED Langen, Karl-Josef UNSPECIFIED orcid.org/0000-0003-1101-5075 UNSPECIFIED Eble, Michael J. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-272060
DOI:	10.1186/s13014-016-0665-z
Journal or Publication Title:	Radiat. Oncol.
Volume:	11
Date:	2016
Publisher:	BMC
Place of Publication:	LONDON
ISSN:	1748-717X
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language HIGH-GRADE GLIOMAS; POSITRON-EMISSION-TOMOGRAPHY; RADIOTHERAPY PLUS CONCOMITANT; O-(2-F-18-FLUOROETHYL)-L-TYROSINE PET; CONFORMAL RADIOTHERAPY; MALIGNANT GLIOMA; DELINEATION; FAILURE; TEMOZOLOMIDE; MULTIFORME Multiple languages Oncology; Radiology, Nuclear Medicine & Medical Imaging Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/27206