ESTRO 36 Abstract Book

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S322 ESTRO 36 2017
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diagnostics, tumor stadium, risk group, localization, initial
symptoms, treatment modalities, toxicities of the
treatments, and survival outcomes were investigated.
Results
A total of 22 patients were identified. Median age was 30.2
years (16.5-45.6 years). All of the patients had de novo
medulloblastoma and good Karnofsky performance status.
The most frequent histologies were classic (n=10) and
desmoplastic (n=9). 2 patients were high risk and 19
standard risk patients. After tumor resection, all the
patients received craniospinal irradiation with a median
dose of 35 Gy and a boost to the posterior fossa with a
median dose of 19.8 Gy. Simultaneous chemotherapy with
vincristine q1w was given to 20 patients. Sequential
chemotherapy with cisplatin/vincristine/CCNU was
applied in 15 patients. 3 patients with recurrent disease
were detected. The median overall survival has not been
reached after a median follow up of 92 months. Estimated
5-year OS was 88% and 10-year OS was 80% respectively.
Estimated 5-year and 10-year-locoregional control was
81% respectively. In univariate analysis shorter
locoregional treatment time (interval of tumor resection
until end of irradiation) was significantly associated with
improved OS (p= 0.031) and improved locoregional control
(p= 0.049). Furthermore anaplastic histology was
associated with worse OS (p<0.01). The most common side
effects were hematological toxicities, with only 2 patients
having had acute grade 3 toxicities.
Conclusion
The combined treatment showed a good outcome in
patients with adult medulloblastoma. The therapy has
been well tolerated. However, further investigations are
needed regarding possible prognostic factors.
PO-0623 Impact of Interim Events during the Surgery-
to-Radiotherapy Interval in Newly Diagnosed
Glioblastoma
C.W. Wee1, E. Kim1 , I.H. Kim1, T.M. Kim2, C.K. Park3,
J.W. Kim 3, S.H. Choi4
1 Seoul National University College of Medicine,
Department of Radiation Oncology, Seoul, Korea
Republic of
2 Seoul National University College of Medicine,
Department of Internal Medicine, Seoul, Korea Republic
of
3 Seoul National University College of Medicine,
Department of Neurosurgery, Seoul, Korea Republic of
4 Seoul National University College of Medicine,
Department of Radiology, Seoul, Korea Republic of
Purpose or Objective
To investigate the impact of interim disease progression
(PD) and other events occurring during the surgery-to-
radiotherapy interval for treatment and outcome in
glioblastoma.
Material and Methods
A total of 222 patients were planned for radiotherapy (RT)
and 173 of them were evaluable for the presence of
interim PD by 2 separate MRIs. The size criteria from the
updated Response Assessment in Neuro-Oncology criteria
was adopted.
Results
Of the 222 patients, 1 patient couldn’t start the planned
RT due to pulmonary complication. All patients with
interim events completed the planned RT. Forty-three
(24.9%) patients experienced interim PD, and their median
survival (MS) was significantly shorter than patients
without PD in univariate (13.9 vs. 18.4 months, p = .002)
and multivariate analysis [ p = .001, HR 2.018 (95% CI,
1.321–3.082)]. Interim non-PD events were observed in 24
(10.9%) patients but did not affect MS compared to those
without non-PD events (20.2 vs. 16.4 months, p = 0.414).
Vascular events and infection of the central nervous
system occurred in 5 (2.3%) and 9 (4.1%) patients,
respectively. Infection significantly prolonged the mean
duration of RT (74.4 vs. 41.2 days, p = .005), but did not
delay RT (37.8 vs. 31.4 days, p = .407) or affect MS (25.5
vs. 16.3 months, p = .562). Vascular events did not
significantly delay RT (36.7 vs. 31.3 days, p = .188),
prolong the duration of RT (33.7 vs. 42.3 days, p = .127),
or affect MS (13.1 vs. 16.7 months, p = .915).
Conclusion
More aggressive treatment strategies such as reoperation
should be investigated in patients with interim PD for
survival improvement. Since a significant portion of
patients demonstrate interim PD, pre-RT MRI is essential
for accurate target delineation. Non-PD events before RT
may affect the duration of RT, but not survival.
PO-0624 Gammaknife Radiosurgery in patients
receiving anticancer immunotherapy: efficacy and
safety
D. Greto1, M. Loi1, S. Scoccianti1, M. Baki1, I. Desideri1, L.
Bordi2, P. Bono 2, I. Meattini1, P. Bonomo1, F. Terziani1, V.
Carfora1, L. Livi1
1Azienda Ospedaliero Universitaria Careggi- Università di
Firenze, Radiotherapy, Firenze, Italy
2Azienda Ospedaliero Universitaria Careggi,
Neurosurgery, Firenze, Italy
Purpose or Objective
Radiosurgery is the treatment of choice for brain
metastasis (BMs) in patients with controlled extracranial
disease under systemic therapy. In recent years, immune
checkpoint inhibitors emerged as a valuable option
resulting in unprecedented long-lasting remissions and
integrated clinical management in patients affected by
metastatic melanoma, lung and kidney cancer. The aim of
the study is to assess the safety and the synergistic activity
of concurrent immune checkpoint inhibitors and
GammaKnife Radio Surgery (GKRS) in a retrospective
cohort of patients.
Material and Methods
We retrospectively reviewed patients undergoing anti
CTLA4 and/or anti PDL1 immunotherapy treated with
GKRS at our Institution from January 2014 to March 2016
for BMs. Radiosurgery was delivered within 6 months from
the last immunotherapy administration. Response to
radiosurgery was evaluated according to RECIST criteria by
magnetic resonance (MRI) performed at 45 days, three and
six months after procedure. Clinical outcome and toxicity
were analyzed and correlated to patient characteristics
and treatment modalities.
Results
Twelve patients (5 melanoma, 6 lung, 1 kidney) were
eligible for a total number of 61 treated lesions for a
median number of 3 lesions per patient (1-16). Median age
was 55 years (32-77) ; median GPA was 2 (1-4). GKRS
consisted of a single session in all patients for a median
dose of 21 Gy (15-24); median treatment volume was 9.45
cm3 (1.75-220.35). Immunotherapy consisted of Anti
CTLA4 (Ipilimumab) in 3 patients, Anti PDL1 (Nivolumab)
in 8 patients or both in 1 case, corresponding to 8 (13.1%),
37 (60.7%), and 16 (26.2%) lesions, respectively. No acute
neurotoxicity occurred after GKRS. MRI at 45 days showed
complete response, partial response and stable disease in
7 (11.5%), 22 (36.1%) and 32 (52.4%) lesions. MRI at 6
months showed progression of treated lesions in 4 (6.6%)
cases; five (41.7%) patients experienced distant brain
failure. At statistical analysis, local control at 6 months
was correlated only to BRAF mutation (p=0.029). At a
median follow up of 9.6 months (6.3-30.6) we recorded
one death due to brain progression while 5 patients died
for extracranial disease; radionecrosis occurred in one
case.
Conclusion
The association of immune checkpoint inhibitors and GKRS
is feasible and did not result in severe toxicity. Enhanced
local control in GKRS treated BRAF mutated melanoma
BMs might result from defective DNA-repair or by