ESTRO 36 Abstract Book

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S604 ESTRO 36
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therapy was used in 78.4% of patients (n = 29). Median
response was 32% (range -39.3% - 78%) comparing week 4
and week 1 nodal volumes. Patients with a response
greater than 32% at week 4 had a 1 year locoregional
control rate of 100% compared with 75.6% for patients
with a ≤ 32% response (p = 0.03). Similarly, patients with
a nodal response > 32% had a 1 year DFS rate of 100% vs.
67.1% for ≤ 32% (p = 0.01).
Conclusion
Nodal response at four weeks may be associated with
ultimate outcome of patients with squamous cell
carcinoma of the head and neck treated with definitive
radiotherapy. While further work is needed, monitoring
of nodal response may allow for both volume and dose
adaptation of therapy.
Electronic Poster: Clinical track: CNS
EP-1101 Leptomeningeal spread after stereotactic
radiation for brain metastases from breast cancer
O. Kaidar-Person1, A. Deal 2, C. Anders3, M. Ewend4, L.
Carey3, E. Dees 3, J. Camporeale1, J. Ramirez5, J.
Benbow5, L. Marks1, T. Zagar1
1 University of North Carolina- Chapel Hill- North
Carolina- USA-, Department of Radiation Oncology,
Chapel Hill, USA
2 UNC Lineberger Comprehensive Cancer Center- Chapel
Hill- NC, Statistics, Chapel Hill, USA
3 University of North Carolina- Chapel Hill- North
Carolina- USA-, Medicine, Chapel Hill, USA
4 University of North Carolina- Chapel Hill- North
Carolina- USA-, Neurosurgery, Chapel Hill, USA
5 University of North Carolina- Chapel Hill- North
Carolina- USA-, UNC Lineberger Comprehensive Cancer
Center- Chapel Hill- NC, Chapel Hill, USA
Purpose or Objective
Our objective was to explore the incidence and predictive
factors for subsequent development of leptomeningeal
disease in women with breast cancer who received
stereotactic radiation (SRT, 1 to 5 fractions) for brain
metastases.
Material and Methods
We conducted a retrospective analysis from a prospective
collected metastatic breast cancer database of all
patients with brain metastases seen between 2012 to
2016.
Results
A total of 98 patients with breast cancer brain metastases
were included. Twenty-one (21%) patients developed
leptomeningeal spread (initial enhancement on MRI,
with/without symptoms). The median time to
development of leptomeningeal spread from the diagnosis
of primary breast cancer was 3.7 years (95% CI 1.3 to 15.3)
and the median time to development of leptomeningeal
spread from the diagnosis of brain metastases was 1.3
years (95% CI 7 days to 4.3 years). All 21 patients
developed symptoms due to leptomeningeal disease. Age,
primary tumor receptor status, Karnofsky performance
status, craniotomy prior to SRT, whole brain irradiation
(WBRT), prior to SRT were not associated with increased
or reduced risk of leptomeningeal spread (all p> 0.05).
Median overall survival from initial diagnosis of
leptomeningeal spread was 2.7 years (95% CI 1.4 to 3.7),
with 2 patients surviving 5 years (5 and 5.3 years).
Conclusion
In this study, we did not identify clinically significant
factors that were associated with an increased risk of
leptomeningeal dissemination. The relatively long overall
survival for breast cancer patients with brain metastases
suggests that brain SRT remains a valid option for breast
cancer brain metastases. Several exceptional responders
with brain metastases and leptomeningeal disease were
identified. A better understanding of this unique
population of patients is needed.
EP-1102 Primary and secondary gliosarcomas: clinical,
molecular, and survival characteristics
H.J. Kim 1, S.H. Kim2, J.H. Chang3, I.J. Lee 1, C.O. Suh 1, J.
Cho1
1Yonsei University, Radiation Oncology, SEOUL, Korea
Republic of
2Yonsei University, Pathology, SEOUL, Korea Republic of
3Yonsei University, Neurosurgery, SEOUL, Korea Republic
of
Purpose or Objective
Gliosarcoma is an extremely rare disease, which is a
variant of glioblastoma exhibiting a biphasic histologic
characteristic of both glial and mesenchymal components.
We investigated to identify prognostic or therapeutic
factors impacting on survival outcomes in patients with
gliosarcoma treated in a single institution.
Material and Methods
Patients who had been treated with a pathology-
confirmed diagnosis of gliosarcoma at Yonsei University
Medical Center between 1991 and 2015 were
retrospectively analyzed. Patients who were ＜20 years
old at diagnosis or have not been followed up after
treatment were excluded. Primary gliosarcoma (PGS) was
defined as a tumor developed de novo, whereas those
diagnosed subsequent to glioblastoma that have been
treated with surgery and adjuvant radiotherapy were
termed secondary gliosarcoma (SGS). Molecular analysis
performed on 9 patients including IDH1, TP53, Ki-67 and
EGFR.
Results
A total of 19 patients were identified, including 17 PGS
and 2 SGS patients. All patients received surgery followed
by adjuvant radiotherapy with a median dose of 60 Gy.
Gross total resection was performed in 6 patients, while
subtotal resection was performed in 13 patients. The
concurrent chemotherapy with temozolomide was
performed in 10 patients. The Median overall survival (OS)
for all patients was 12.9 months from the diagnosis of
gliosarcoma, with a progression free survival (PFS) of 5.5
months. The median OSs were 12.9 and 5.2 months for PGS
and SGS, respectively (P = 0.035) and the median PFSs
were 6.1 and 0.8 months (P = 0.048). In the two cases of
SGS, SGS developed 10 and 18 months after the diagnosis
of GBM for each. The univariate analysis revealed that
good performance status (KPS ≥ 80), PGS and salvage
treatment after recurrence were significant prognostic
factors related to better OS. All these factors were also
remained as independent prognostic factors for OS in the
multivariate analysis. Molecular analysis revealed a high
incidence of P53 expressions and, rarely, EGFR and IDH1
mutations.
Conclusion
Primary and secondary gliosarcoma had an even poorer
survival, compared with primary and recurrent
glioblastoma, respectively. Further molecular marker
study should be done to explain the dismal prognosis of
gliosarcoma. And multi-institutional collaborative study is
needed to characterize prognostic factors and design
optimal treatment.
EP-1103 Are hippocampi considered organs at risks
during stereotactic radiotherapy for brain metastases?
U. Tebano 1, A. Fiorentino1, G. Sicignano1, N. Giaj-Levra1,
S. Fersino1, R. Mazzola1, F. Ricchetti1, S. Naccarato1, R.
Ruggieri1, F. Alongi1
1Sacro Cuore Don Calabria Cancer Care Center, Radiation
Oncology Division, Negrar, Italy