Alonso, R.

Chen, X.

Ciervide Jurio, R.

Garcia-Aranda Pez, M.

Guimaraes Domingos da Silva, R.

Hernando Requejo, O.

Lopez Gonzalez, M.

Montero Luis, A.

Payano Hernandez, S.

Rodriguez, A.

Rubio Rodriguez, C.

Sanchez Saugar, E.

Valero Albarrán, J.

Elsevier - Publisher Connector 

S536                                                                                                                                                  ESTRO 35 2016 
_____________________________________________________________________________________________________ 
control rates and may ultimately improve OS. The 
combination of surgery followed by RT appears to be the 
current standard of care.  
 
EP-1115 
Stereotactic radiosurgery for brain metastases: 
neuropathological report of three autopsy cases 
M. Sakuramachi
1Tokyo University, Radiology, Tokyo, Japan 
1, H. Igaki2, A. Nomoto1, N. Sekiya1, W. 
Takahashi1, K. Ookuma1, M. Ikemura3, H. Yamashita1, K. 
Nakagawa1 
2National Cancer Center, Radiation Oncology, Tokyo, Japan 
3Tokyo University, Pathology, Tokyo, Japan 
 
Purpose or Objective: To elucidate the radiobiological 
effects of stereotactic radiosurgery (SRS) on brain metastases 
using autopsy cases. 
 
Material and Methods: From 1995 to 2013, 9 brain specimens 
from 3 patients were available. They underwent autopsy 
after SRS in our hospital. These specimens were all brain 
metastases. The timing of autopsy was from 7 days to 20 
months (median 10 months) after SRS. The 9 tumors received 
a margin dose of 16–20 Gy (median 20 Gy) at the 40–75% 
isodose line (median 40%), with a maximal dose of 16–50 Gy 
(median 45 Gy). Histopathological investigations were 
performed. The specimens were fixed in 20% neutral buffered 
formaldehyde and embedded in paraffin. Hematoxylin-eosin, 
Azan-Mallory, and Bodian stains were used. 
Immunohistochemical reactions included glial fibrillary acidic 
protein, alpha-smooth muscle actin, CD34, and CD68 
antigens. Ki67 and p53 reactions were also used. 
 
Results: The first case was a 59-year-old man diagnosed with 
2 brain metastases from renal cell carcinoma. Both lesions 
were irradiated with SRS. He received SRS 4 times after the 
first SRS. At 1 week after the last SRS, he died from 
carcinomatous lymphangiosis. The second case was a 63-year-
old man diagnosed with 2 brain metastases from lung cancer. 
Both lesions were irradiated with SRS plus whole brain 
radiotherapy (WBRT). Seven months later, he died from 
carcinomatous peritonitis. The third case was a 35-year-old 
woman diagnosed with 2 brain metastases from breast 
cancer. Both lesions were irradiated with WBRT plus SRS. 
When one of the lesions enlarged 1 year later, repeated SRS 
was performed. At 7 months after reirradiation, she died 
from carcinomatous lymphangiosis. In the first case, necrosis 
and viable tumor cells were observed mainly in the center of 
the lesion at 1 week after SRS, while apoptosis and fibrosis 
were observed in a small part of the lesion. Glial cells and 
neutrophilic leukocytes had accumulated around the lesion. 
In the lesions at 2 months after SRS, tumor cells and fibrosis 
were not observed; only macrophages and glial cells were 
observed in the SRS irradiated field. In the second case, 
fibrosis was observed at the periphery of the center necrotic 
region at 7 months after SRS. In the third case, almost all 
parts of the lesions were replaced with fibrosis at 19 months 
after SRS, while small foci of viable tumor cells, a large 
number of glial cells, and macrophages were observed around 
the fibrotic area. 
 
Conclusion: In the tumors, apoptosis was only observed at 1 
week after SRS. The time of fibrosis initiation varied in each 
case. Around the tumors, neutrophilic leukocytes and glial 
cells accumulated within 1 week after SRS. Macrophages 
accumulated at least 2 months after SRS. Stromal changes 
remained for a considerable period of time. It was 
remarkable that fibrosis occurred very soon after SRS, and 
other observations were generally compatible with previous 
reports. 
 
EP-1116  
Staged radiosurgery for petroclival meningiomas: 
preliminary results 
V. Pinzi
1IRCCS Istituto C. Besta, Neurosurgery Radiotherapy Unit, 
Milan, Italy 
1, M. Marchetti1, I. Milanesi1, E. De Martin2, L. 
Fariselli1 
2IRCCS Istituto C. Besta, Health Department-, Milan, Italy 
 
Purpose or Objective: The goal of surgical treatment of 
meningiomas is the total resection of the tumour. The 
complete removal of petroclival meningiomas can be difficult 
because of their proximity to cranial nerves. Stereotactic 
radiosurgery (SRS) is a well established treatment for many 
patients with intracranial meningiomas, either in the 
exclusive or adjuvant setting. However, SRS of large 
meningiomas might be associated with significant morbidity. 
Under these circumstances s-SRS has the potential to deliver 
sharply focused high doses per fraction without increasing the 
risk of toxicity.The aim of this study is to prospectively 
evaluate the feasibility of s-SRS for petroclival meningiomas, 
including large volume lesions. 
 
Material and Methods: Between September 2011 and 
October 2013 at our Institute, s-SRS using the CyberKnife was 
prospectively performed on 30 patients (24 women and 6 
men, men, mean age 57 years) with petroclival meningiomas. 
Patients with atypical or malignant meningiomas and those 
who had received prior radiotherapy were excluded. The 
average tumor volume was 11,86 cm3 (range 2,2–126,3 cm3); 
the average tumor prescription dose was 24,4 Gy, the number 
of fraction was 4 or 5. 
 
Results: After a median follow-up of 30 months (range 13-36 
months ) the overall tumour control rate was 100% (25 
patients with stable disease, 3 patients with partial response 
and 2 patients with complete response). Tumor control rates 
at 2 and 3 years was 100%. Among 28 patients who were 
symptomatic before staged radiosurgery, neurological follow-
up showed an improvement in 43%, stable clinical course in 
43% and a persistent deterioration of clinical symptoms in 
14% of the patients. A transient neurological deterioration 
was observed in 11% of patients within the first year after 
treatment. 
 
Conclusion: Our findings show that s-SRS using the 
CyberKnife is a safe and effective option in the treatment of 
large-volume petroclival meningiomas. A good tumour control 
and a low morbidity rate was achieved in our series, either as 
a primary or adjuvant approach. Long-term follow-up is 
warranted to confirm these results. 
 
EP-1117  
Frameless radiosurgery for acoustic schwannoma: a five-
year experience 
S. Payano Hernandez
1Hospital Universitario Madrid Sanchinarro - Grupo Hospital 
de Madrid, Oncologia Radioterápica, Madrid, Spain 
1, O. Hernando Requejo1, M. Lopez 
Gonzalez1, E. Sanchez Saugar1, M. Garcia-Aranda Pez1, J. 
Valero Albarrán1, A. Montero Luis1, R. Ciervide Jurio1, A. 
Rodriguez1, R. Alonso1, X. Chen1, C. Rubio Rodriguez1, R. 
Guimaraes Domingos da Silva1 
 
Purpose or Objective: Frameless radiosurgery (SRS) plays an 
important role in the management of acoustic neuromas. This 
retrospective study aims to evaluate tumor control using this 
technique.  
 
Material and Methods: Thirty four patients with unilateral 
acoustic neuromas (vestibular schwannomas) who underwent 
linear accelerator-based frameless SRS at low dose (12 Gy) to 
the tumor from July 2008 to February 2015 were evaluated. 
Twenty-one patients were male and 13 patients were female. 
The median age was 62 years (range 23-84) with a median 
follow-up period of 12.4 months (range 1-60). Treatment 
volume was 0.1 to 3.8 cm3 (median 0.93 cm3 ). 
 
Results: Preliminary results from follow-up magnetic 
resonance imaging (MRI) showed: the tumor of 15 patients 
decreased in diameter, no changes was found in 14 and the 
tumor increased slightly in only one patient. All patients are 
alive, except for 1p who died from intercurrent disease 2 
years after radiosurgery. Among 23p with acufeno, full 
improvement was demonstrated in four. There were no 
reported complications related to treatment.  
ESTRO 35 2016                                                                                                                                                    S537 
________________________________________________________________________________ 
 
Conclusion: We experienced excellent short term local 
control and low incidence of complication for acoustic 
schwannomas undergoing frameless SRS treatment. Our data 
compare favorably with the literature. Additional follow-up 
will be necessary to evaluate long term results of treatment. 
 
EP-1118  
Impact of susceptibility-weighted imaging MRI on 
radiosurgery for melanoma and RCC brain metastases 
A. Klimov
1Saint Petersburg State University, Faculty of Surgery, Saint 
Petersburg, Russian Federation 
1,2, S. Rogers2, L. Boxheimer3, S. Bodis2 
2Canton Hospital Aarau, Institute of Radiation Oncology, 
Aarau, Switzerland 
3Canton Hospital Aarau, Department of Neuro-radiology, 
Aarau, Switzerland 
 
Purpose or Objective: A patient with malignant melanoma 
and 4 visible lesions on a gadolinium (Gd)-enhanced T1 MRI 
scan of the brain was reported at the tumor board as having 
at least 7 probable metastases on the basis of the matching 
susceptibility-weighted imaging (SWI). SWI detects cerebral 
microbleeds and may therefore be more sensitive than Gd-T1 
MRI in the detection of small haemorrhagic metastases and 
prediction of future sites of intra-cranial relapse. Our aim 
was to explore the potential usefulness of SWI in 1) the 
selection for radiosurgery and 2) the follow-up of patients 
with brain metastases from malignant melanoma and renal 
cell carcinoma (RCC). 
 
Material and Methods: At the time of referral for 
radiosurgery, a 3-D Gd-T1 MRI was evaluated at the neuro-
oncology multidisciplinary tumor board to determine the 
number of brain metastases. We retrospectively analysed the 
synchronous SWI sequence to explore any difference in the 
number of detectable lesions and hence putative metastases. 
Subsequent enhanced T1-weighted MRIs were evaluated for 
new metastases at the site of SWI abnormalities. 
 
Results: T1 MRI scans detected 16 metastases in a sample of 
11 patients with melanoma and RCC who were treated with 
primary or postoperative linear accelerator-based 
radiosurgery in our center. 25 regions of signal change were 
detectable on the matching SWI sequences. The scans were 
reviewed by a board-certified neuro-radiologist who 
confirmed that the 9 additional SWI lesions were non-
metatastic. To date, none of the additional lesions have 
developed into enhancing brain metastases. Indeed, 
additional SWI changes on postoperative imaging resolved 
completely on subsequent imaging. Thus the 16 SWI changes 
with metastatic features correlated perfectly with the 16 
metastases on Gd-T1 MRI. (Figure 1) 
 
 
 
Conclusion: SWI sensitively detects blood products in primary 
and secondary brain tumours, but also in veins, vascular 
malformations and postop-operative bleeding and 
calcification. An expert neuro-radiology opinion in the 
context of the tumour board is essential for the accurate 
interpretation of SWI to avoid “overdiagnosis” of metastases, 
particularly in the post-operative setting. Occasionally 
however, additional lesions that are highly suspicious for 
metastases may be detected on SWI. The sensitivity and 
specificity of SWI for metastases should be determined in a 
larger cohort as it may assist patient selection for 
radiosurgery in borderline cases. 
 
EP-1119  
Treatment of Subependymal giant cell astrocytoma (SEGA): 
Is there a place for radiotherapy? 
R. Atef Kamel
1Universitair Ziekenhuis Brussel, Department Radiotherapy, 
Brussels, Belgium 
1 
 
Purpose or Objective: SEGA is a WHO grade I glioma that is 
almost exclusively seen in young patients with tuberous 
sclerosis complex (TSC). Despite the benign histology, SEGA 
can be severely symptomatic as it typically arises 
intraventricularly and can cause obstructive hydrocephalus. 
The current standard treatment of SEGA includes surgical 
resection and chemotherapy, the m-TOR inhibitor 
everolimus. Based on expert opinion, there is an 
international consensus that radiotherapy should not be used 
in the treatment of SEGA.  
Here, we present a case of a patient with TSC, with 
inoperable bilateral ventricular SEGA. Years long before the 
availability of everolimus or its approval for treating SEGA, 
we treated this patient exclusively with radiotherapy.  
 
Material and Methods: With stereotactic fractionated 
radiotherapy, a dose of 60 Gy in 30 fractions of 2 Gy, was 
delivered on the GTV. The patient was afterwards followed 
up with MR imaging. We did volumetric assessment of tumour 
size on each follow up MRI and tracked the changes in tumour 
size after radiotherapy.  
We performed an extensive literature study to verify the 
sources of the consensus against radiotherapy in treatment of 
SEGA. 
 
Results: The patient tolerated the treatment very well. No 
acute or chronic side effects were seen. A follow up over a 
period of 8 years, using MR imaging, showed about 70% 
decrease in tumour volume.  
We found that the advice against radiotherapy appears to be 
based on very little, if any, evidence. 
 
Conclusion: Radiotherapy can be a potential useful tool in 
the treatment of SEGA. The slow but progressive response of 
SEGA to radiotherapy resembles what is seen in other benign 
brain tumors e.g. meningioma. Radiotherapy has been 
discarded prematurely as a therapeutic option for SEGA and 
could be very well used to consolidate effect of everolimus. 
Prospective registration of patients and treatment outcome is 
needed to enhance knowledge. 
 
EP-1120  
Experience with robotic SBRT in treatment of intraspinal 
tumours 
R. Garcia1, A. Velazquez-Pacheco
1Instituto Madrileno de Oncologia, Centro de Radioterapia y 
Radiocirugía Robotizada Cyberknife, Madrid, Spain 
1, I. Marrone1, I. Santa-
Olalla1 
 
Purpose or Objective: The role of radiotherapy in the 
treatment of intraspinal tumors constitutes a paradigm, 
justified by tolerance of spinal cord. Advances in SBRT 
(Stereotactic Body Radiation Therapy) as robotic and image-
guided treatments have revolutionized in this group. The aim 
of this study is to analyze our preliminary experience treating 
intraspinal tumors using robotic SBRT. 
 
Material and Methods: Clinical and dosimetric data on 19 
patients between 2011 and 2015 were reviewed, patients 
with lesions in spinal canal including intramedullary and 
intradural extramedullary were selected solely. All patients 
were treated with robotic SBRT image-guided in real time 
(Cyberknife). 


EP-1117: Frameless radiosurgery for acoustic schwannoma: a five year experience 

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EP-1117: Frameless radiosurgery for acoustic schwannoma: a five year experience

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