Recurrence pattern after [(18)F]fluoroethyltyrosine-positron emission tomography-guided radiotherapy for high-grade glioma: a prospective study.
OBJECTIVE
To assess the failure pattern observed after (18)F fluoroethyltyrosine (FET) planning after chemo- and radiotherapy (RT) for high-grade glioma.


METHODS
All patients underwent prospectively RT planning using morphological gross tumour volumes (GTVs) and biological tumour volumes (BTVs). The post-treatment recurrence tumour volumes (RTVs) of 10 patients were transferred on their CT planning. First, failure patterns were defined in terms of percentage of RTV located outside the GTV and BTV. Second, the location of the RTV with respect to the delivered dose distribution was assessed using the RTV's DVHs. Recurrences with >95% of their volume within 95% isodose line were considered as central recurrences. Finally, the relationship between survival and GTV/BTV mismatches was assessed.


RESULTS
The median percentages of RTV outside the GTV and BTV were 41.8% (range, 10.5-92.4) and 62.8% (range, 34.2-81.1), respectively. The majority of recurrences (90%) were centrally located. Using a composite target volume planning formalism, the degree of GTV and BTV mismatch did not correlate with survivorship.


CONCLUSIONS
The observed failure pattern after FET-PET planning and chemo-RT is primarily central. The target mismatch-survival data suggest that using FET-PET planning may counteract the possibility of BTV-related progression, which may have a detrimental effect on survival.
Weber
Damien C
DC
Department of Radiation Oncology, and; Department of Radiation Oncology, University of Geneva, Geneva, Switzerland. damien.weber@medecine.unige.ch
Casanova
Nathalie
N
Zilli
Thomas
T
Buchegger
Franz
F
Rouzaud
Michel
M
Nouet
Philippe
P
Vees
Hansjorg
H
Ratib
Osman
O
Dipasquale
Giovanna
G
Miralbell
Raymond
R
D000328:Adult; D000368:Aged; D001254:Astrocytoma / Q000000981:diagnostic imaging / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D001932:Brain Neoplasms / Q000000981:diagnostic imaging / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D005260:Female; D019788:Fluorodeoxyglucose F18; D005909:Glioblastoma / Q000000981:diagnostic imaging / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D049268:Positron-Emission Tomography; D019275:Radiopharmaceuticals; D011880:Radiotherapy Planning, Computer-Assisted; D016019:Survival Analysis; D015996:Survival Rate
D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18