ESTRO 36 Abstract Book

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S262 ESTRO 36 2017
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Montreal, Canada
4 McGIll University Health Center, Clinical Statistics,
Montreal, Canada
5 McGIll University Health Center, Medical physics,
Montreal, Canada
6 McGIll University Health Center, Pathology, Montreal,
Canada
Purpose or Objective
The role of adjuvant radiotherapy (RT) in the post-
operative management of atypical meningiomas remains
controversial, particularly after a gross total resection
(GTR). In this study, we reviewed long-term results in such
patients aiming to identify patient-, tumor- or treatment-
related variables potentially associated with prognostic
significance that might influence outcomes.
Material and Methods
Between 1992 and 2013, we retrospectively identified 72
patients with atypical meningioma treated at our
institution. All of them underwent a maximal safe surgical
resection. Patients with multiple tumors,
neurofibromatosis type 2, previous cranial RT, multiple
lesions, previously resected grade I lesion that had
transformed to a grade II at time of recurrence or
inadequate follow-up imaging were not eligible. Pathology
was reviewed in each case to confirm grading. We
performed pre- and post-operative serial planimetric and
volumetric measurements of tumor size changes from
magnetic resonance imaging. Age, tumor location, bone
involvement, extent of resection, tumor growth rate, use
of post-operative radiotherapy (PORT), and residual tumor
volume at time of radiotherapy (RT) were assessed by uni-
and multivariate analysis to determine their influence on
local tumor progression. We measured, before and after
RT, absolute and relative tumor growth rates and tumor
doubling time in all patients.
Results
Median age was 62 years and the median follow-up was 69
months. Forty-two patients (58%) underwent GTR and 30
(42%) underwent a subtotal resection (STR). PORT was
delivered to 12 patients (28.5%) with GTR and only 4 (13%)
with subtotal resection (STR). Control rates at 5 years for
GTR patients with or without PORT were 100% vs. 53%
(median time for failure = 30 months), respectively
(p=0.0034). Similarly, local control for STR patients +/-
PORT were 75% vs 4% (median time for failure = 10
months), respectively (p=0.0038). On multivariate
analysis, no-PORT (p=0.01) and STR (p=0.0002) were the
only independent significant prognostic factors for local
recurrence. Based on Youden-Index-J, a cut-off residual
volume of less than 8.76 cm 3 was associated with lower
failure rate (7% vs 77 %, p<0.001). In patients not receiving
RT, the median relative and absolute growth rates, and
tumor doubling time were 115.75%/year, 4.27 cm3/year
and 0.78 year, respectively. These indices improved after
the addition of RT (74.5%/year, 2.48c cm 3/year and 1.73
year, respectively). Volumetric measurement detected
tumor progression earlier than planimetric by a median
time lag of 18 months.
Conclusion
In patients with atypical meningioma, regardless of
whether a GTR or STR is performed, the use of PORT
appears to be associated with significant improvement in
local disease control. Patients with a residual tumor larger
than 8.76 cm3 have an increased failure rate and should
be considered for early RT.
PV-0503 Novel RPA classification combining MGMT
promoter methylation status in newly diagnosed
glioblastoma
C.W. Wee1, E. Kim1 , I.A. Kim1, T.M. Kim2, Y.J. Kim2, C.K.
Park3, J.W. Kim3, C.Y. Kim 3, S.H. Choi4, J.H. Kim 4, S.H.
Park5, G. Choe5, S.T. Lee6, I.H. Kim1
1 Seoul National University College of Medicine,
Department of Radiation Oncology, Seoul, Korea
Republic of
2Seoul National University College of Medicine,
Department of Internal Medicine, Seoul, Korea Republic
of
3Seoul National University College of Medicine,
Department of Neurosurgery, Seoul, Korea Republic of
4Seoul National University College of Medicine,
Department of Radiology, Seoul, Korea Republic of
5Seoul National University College of Medicine,
Department of Pathology, Seoul, Korea Republic of
6Seoul National University College of Medicine,
Department of Neurology, Seoul, Korea Republic of
Purpose or Objective
Since the prognostic and predictive value of MGMT
promoter methylation is widely understood, a refinement
of the recursive partitioning analysis (RPA) classification
for glioblastoma (GBM) integrating the MGMT methylation
status is warranted.
Material and Methods
A total of 256 patients since 2006 were prospectively
intended to be treated with radiotherapy (RT) plus
concurrent and adjuvant temozolomide (TMZ) according
to the standard regimen and the MGMT methylation status
was available in all patients. In 45.3 % of the patients, the
MGMT promoter was methylated.
Results
The median follow-up and survival (MS) were 17.7 and 19.6
months, respectively. RPA was performed based on the
results of multivariate analysis, and in contrast to the
RTOG RPA classification, Karnofsky performance status
(KPS) score made the initial split (≥70 vs. <70). Four RPA
classes were identified (p < .001); class I,
KPS≥70/GTR/methylated MGMT (MS 69.2 months); class II,
KPS≥70/GTR/non-methylated MGMT or KPS≥70/residual
disease/methylated MGMT (MS 23.7 months); class III,
KPS≥70/residual disease/non-methylated MGMT (MS 15.4
months); class IV, KPS<70 (MS 11.0 months).
Conclusion
A novel RPA classification for GBM was formulated
highlighting the significance of MGMT promoter
methylation in the TMZ era. This model integrating
pertinent molecular information can be used effectively
for the prediction of individual patient’s prognosis.
PV-0504 Observed survival in 3270 patients treated
with Whole Brain Radiotherapy compared to the
QUARTZ data
P. Jeene 1, R. Kwakman1, J. Van Nes 2, K. De Vries3, G.
Wester4, E. Dieleman1, T. Rozema5, J. Zindler6, J.
Verhoeff7, L. Stalpers1
1Academic Medical Center, Radiotherapy, Amsterdam,
The Netherlands
2Radiotherapeutisch Instituut Friesland, Radiotherapy,
Leeuwarden, The Netherlands
3Antoni van Leeuwenhoek, Radiotherapy, Amsterdam,
The Netherlands
4Radiotherapiegroep, Radiotherapy, Arnhem, The
Netherlands
5Instituut Verbeeten, Radiotherapy, Tilburg, The
Netherlands
6MAASTRO Clinic, Radiotherapy, Maastricht, The
Netherlands
7Academic Medical Center Utrecht, Radiotherapy,
Utrecht, The Netherlands
Purpose or Objective
Since Horton et al (1971), Whole Brain RadioTherapy
(WBRT) is considered the standard of care for patients
with more than 3 brain metastases or patients otherwise
unfit for radical local treatment and with at least a
reasonable performance score. In the 2016 QUARTZ trial,
patients with brain metastases from a primary non-small
cell lung cancer (NSCLC) were randomized between best
supportive care (BSC) and WBRT with BSC. There was no