ESTRO 36 Abstract Book

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S602 ESTRO 36 2017
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Material and Methods
33 patients diagnosed with HGG, aged 25-71 (median 57),
were re-irradiated due to tumor progression between 2011
and 2014. All patients underwent neurosurgery at the time
of primary diagnosis (2008-2012). Pathology was:
anaplastic astrocytoma G3 in 2 patients, and glioblastoma
G4 in 31 patients. The surgery was followed by concurrent
radiochemotherapy with temozolomide. All patients
completed the treatment receiving 60 Gy. During follow-
up gadolinium-enhanced MRI was performed every 3
months. Recurrence was found in MRI scans 3-54 months
after completion of treatment (median time to recurrence
was 9 months). In 8 patients partial tumor resection was
performed (pathology was confirmed as glioblastoma G4
in this group). All patients were planned for re-irradiation.
CyberKnife® stereotactic radiation therapy was used.
Total dose and dose per fraction delivered to tumor
depeneded mainly on tumor volume and time interval
after the first course of radiation therapy. The irradiated
tumor volume ranged from 9.4 to 75.7 cm3. 4 patients
received 18 Gy in 3 fractions, 14 patients – 16 Gy in 2
fractions, 11 patients – 12 Gy in 2 fractions, and 4 patients
– 8 Gy in a single fraction.
Results
All patients completed the stereotactic radiation therapy.
82% of patients reported mild or moderate headache
(CTCAE grade 1 or 2). No grade 3 or 4 acute toxicity was
observed. Follow-up time after re-irradiation was 3 – 48
months (median 12 months). Progression-free survival was
3 – 39 months (median 6 months). The early results were
assessed with MRI scans performed 3 months after the
stereotactic radiation therapy. Stable disease was
observed in 5 patients (15.2%). Partial tumor regression
was observed in 6 patients (18.2%).
Conclusion
In our experience, CyberKnife ® stereotactic radiation
therapy can be considered as a valuable treatment option,
which can slow down the inevitable progression of high
grade gliomas in about 30% of patients. It also seems to be
a safe method of re-irradiation, provided that the total
dose and dose per fraction are chosen carefully and
individually.
EP-1109 measurement of hippocampus atrophy after
whole brain irradiation using voxel based
morphometry
T. Ito1, Ｍ. Nishihara2, S. Takaki2, Y. Tani2
1 Japanease Redcross society nagaoka hospital, radiaton
therapy, Nagaoka, Japan
2 Japanease Redcross society nagaoka hospital, radiology,
Nagaoka, Japan
Purpose or Objective
To estimate the adverse effect of whole brain radiation
therapy (WBRT), especially cognitive disorder, we
measured retrospectively about mesial temporal lobe size
after WBRT using voxle based morphometry in cancer
patients.
Material and Methods
From 2013 to 2015 ,11 cancer patients with multiple brain
metastasis ( 7 men and 4 women , average age was 59
years) were examined by gadrinium enhanced MRI before
and after WBRT. The sequence was followed; T1-weighted
3D-variable flip angle sagital image in 1mm slice thickness
,using 1.5T MRI scanner, and it is routine sequence in our
hospital for cancer patient's examination.
And this image set was analysed ｂｙ voxel based
morphometry from the view point of the ratio of the
mesial temporal lobe to the whole brain . Voxel based
morphometry software was VSRAD advanced 2 ,and this
program was generally used for Alzheimer's disease
evaluation.
Images were obtained before WBRT, and after several
month in variable periods.(longesｔ case was 14 months)
Results
33 MRI image was analysed and calculate by VSRAD
advanced2 . The examinations with severe brain edema or
huge metastasis were excluded . 2 patients were alive and
9 patients were dead by original disease ( include caused
by brain metastasis) . In only one patient, mental
disturbance was occurred clinically,but other patients
were not reported metal disorder by clinician. No patient
was examined mini-mental state examination.
Temporary increase tendency of hippocampus atrophy
compared to whole brain were observed in the period of
about 4 months after WBRT. But reliability was low
statistically.
Conclusion
A minimal change of hippocampus size was observed , but
it might be a measurement error . Further investigation is
needed ,especially more number of cases.
Furthermore, from the perspective of with or without of
chemotherapy, or comparison to after stereotactic
radiosurgery aleno are required.
EP-1110 Evaluation of [18F]FET-PET and MRI assessed
recurrence pattern in patients with high-grade glioma
J. Hesse1,2, K. Kessel1, H. Specht1, M. Schwaiger3, T.
Pyka3, C. Zimmer4, S. Combs1,2
1Technical University Munich TUM, Department of
Radiation Oncology, München, Germany
2Institute of Innovative Radiotherapy iRT, Department of
Radiation Sciences DRS, Neuherberg, Germany
3Technical University Munich TUM, Nuclear Medicine,
München, Germany
4Technical University Munich TUM, Department of
Neuroradiology, München, Germany
Purpose or Objective
Despite multidisciplinary therapy concepts the prognosis
of high-grade glioma (HGG) remains poor and recurrence
is frequent. In this analysis, we evaluated the recurrence
pattern and gross tumor volume (GTV) comparing two
different imaging techniques: MRI and [ 18F]FET-PET. Our
aim was to identify high-risk areas for recurrence in order
to optimize concepts of radiotherapy-planning.
Material and Methods
We analyzed 14 patients with HGG (WHO °III: n=6, WHO
°IV: n=8) treated in our department. All patients were
incompletely resected received adjuvant radiotherapy.
GTV and tumor volume at recurrence (RecTV) definition
was based on MRI (GTV MRI, RecTVMRI) and FET-PET (GTVPET,
RecTVPET). In order to evaluate the recurrence pattern,
the percentage of RecTVPET and RecTVMRI residing within
the planning target volume (PTV) was determined. We
classified RecTV as 'in-field” if more than 90% of RecTV
was detected inside PTV, as 'field-border” if 30-90% and as
'out-field” if less than 30% was located within PTV. We
compared the volumes and calculated various intersection
(IV) and conjunction volumes (CV) as well as the
conformity index (CI=IV/CV). CI takes not only volumetric
size into account, but also the extend of overlap. For