Recurrence pattern after [(18)F]Fluoroethyltyrosine-Positron Emission Tomography-guided radiotherapy for high-grade glioma: A prospective study
Received 13 November 2008; received in revised form 21 August 2009; accepted 30 August 2009. published online 27 September 2009.
Abstract
Purpose
To assess the failure pattern observed after 18F 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.
ABSTRACT