International Journal of Radiation Oncology � Biology � PhysicsS726

Purpose/Objective(s): Ewing sarcoma (EWS) is a rare tumor with 200

cases per year with a median age at diagnosis of 14-15 years. EWS is

currently managed with chemotherapy, surgery and/ or radiation therapy.

Radiation therapy can be given in the adjuvant setting or definitively for

local therapy in settings where surgery would result in a functional

impairment. Large trials with EWS are difficult due to its rarity. The

Surveillance, Epidemiology and End-Results (SEER) is a cancer registry

overseen by the National Cancer Institute that offers an opportunity to

perform large population studies in patients EWS. The purpose of this

study is to use a national population-based database to compare the overall

survival (OS) in patients who received surgery alone (SA), surgery and

radiation therapy (SRT), radiation therapy alone (RT), or neither surgery

nor radiation therapy (NSR) in patients with EWS.

Materials/Methods: The National Cancer Institute’s SEER registry was

queried to identify patients under the age of 19 diagnosed with EWS (n Z1302) reported during 1973-2010. SPSS 22 was used to compare the OS

using the Friedman Test and Wilcoxon Signed Ranks Test in the cohort of

patients receiving SA, SRT, RT, or NSR.

Results: Of the 1302 patients with EWS, 28 were excluded due to no docu-

mentation of whether surgery and/ or radiation was administered, leaving 1274

patients for analysis. Of these, there were 386 patients with EWS treated with

SA, 300 patients treated with SRT, 385 treated with RT, and 203 treated with

NSR. The median OS in patients receiving SAwas 55 months with a mean OS

of 82.80 months, median OS in patients receiving SRTwas 46 months with a

mean OS of 84.24 months, the median OS in patients receiving RT was 39

months with a mean OS of 90.14 months, and the median OS in patients

receiving NSR was 27 months with a mean OS of 70.90 months (p<.001).

When comparing OS between groups, there was a statistically significant

difference when comparing OS between SA and NSR (p<.001), RTand NSR

(p<.001), and SRTand NSR (pZ .001). Therewas no statistically significant

difference when comparing the patients treated with SA and RT (pZ 0.634),

SRT and RT (p Z .229), and SRT and SA (pZ .102).

Conclusions: This study describes differences in OS by treatment modality

in patients with EWS. One limitation of this study is it does not take into

account systemic therapy, which is one of the mainstays of treatment.

Another limitation is this study does not take into account the performance

status of the patient. This study suggests that patients with EWS treated

with radiation alone have a similar OS to those treated with surgery alone

or surgery and radiation, and that radiation alone may be non- inferior to

patients treated with surgical management.

Author Disclosure: W. Haque: None. B. Ager: None. S.S. Hatch: None.

3309Primary Mediastinal and Thoracic Liposarcomas: Clinical Analysisof 25 CasesJ. Liang, D. Chen, L. Liu, and L. Wang; Cancer Hospital, Chinese

Academy of Medical Sciences, Beijing, China

Purpose/Objective(s): Analyze the clinical characteristics of primary

mediastinal and thoracic liposarcomas.

Materials/Methods: Data of mediastinal and thoracic liposarcomas for the

period 1970 to 2012 were searched in our Cancer Hospital. 25 cases had

been identified by surgical pathology or biopsy pathology. All cases were

according to diagnostic criteria for liposarcoma subtypes.

Results: Themedian age at diagnosiswas 45years old (range 20-63). Therewere17 male and 8 female patients. The most initial symptomwas shortness of breath

and oppression in the chest in 11 (44%) patients. The locations of the primary

tumorwere anteriormediastinum in 14 (56%) patients, posteriormediastinum in 6

(24%) patients, pleura in 3 (12%) patients and pulmonary in 2 (12%) patients. The

median tumor sizewas 9 cm (range 7-25), which less than 9 cmwere in 10 (40%)

patients and more than 9 cm were in 15 (60%) patients. Eight (32%) cases, 11

(44%)cases, 4 (16%)cases and 2 (8%) cases were well differentiated, myxoid,

pleomorphic and dedifferentiated liposarcomas, respectively. Twenty-three (92%)

patients had undergone surgery, including 15 completed resection and 8 incom-

pleted resection. Twelve (48%) patients had received radiation therapy (RT) with

total dose 20 to 66 Gy in 10 to 33 fractions. At one month after the treatment, 16

(64%) of 25 patients had attained CR; 7 (28%) patients had achieved PR, while 2

(8%) patients showed SD and none PD, respectively. The 5-year local recurrence

ratewas 52%, and the distancemetastasis ratewas 32%.Themedian survival time

(MST) of 25 patients was 60 months, the 3-year, 4-year and 5-year OS were

66.8%, 57.2% and 45.8%, respectively. The median progress free survival time

(MPFST) of 25 patients was 24 months, the 2-year, 3-year and 4-year PFS were

47.1%, 30% and 25%, respectively. The median local recurrence free survival

time (MLRFST) of 25 patients was 35months, the 3-year, 4-year and 5-year local

recurrence free survival (LRPFS) were 44.2%, 44.2% and 33.1%, respectively.

The multivariate analysis of OS show completed resection had significant dif-

ference with P Z 0.049 and pathology group had nearly significant difference

with P Z 0.057. The multivariate analysis of PFS show pathology group and

completed resection had significant difference with P Z 0.004 and 0.043,

respectively. The multivariate analysis of LRFS show only pathology group had

significant difference with PZ 0.02.

Conclusions: For patients with primary mediastinal and thoracic lip-

osarcomas, well differentiated liposarcoma and completed resection are

associated with more favorable survival. Completed resection deserved to

be recommended. More effective adjuvant therapies need further study.

Author Disclosure: J. Liang: None. D. Chen: None. L. Liu: None. L.

Wang: None.

3310High-Precision Involved-Lesion Radiation Therapy (IL-RT) to allMetastatic Sites in Multifocal Pediatric SarcomaB. Roeper,1 B. Woeller,1 N. Andratschke,1,2 A. Wawer,3 S. Kampfer,1

M. Hadjamu,1 I. Teichert von Luettichau,3 U. Thiel,3 M. Molls,1

and S.E.G. Burdach3; 1Department of Radiation Oncology, Klinikum

rechts der Isar, Technische Universitaet Muenchen, Munich, Germany,2Department of Radiation Oncology, Universitaetsspital Zuerich, Zurich,

Switzerland, 3Department of Pediatrics, Technische Universitaet Munchen,

Munich, Germany

Purpose/Objective(s): As some data suggested that pediatric sarcoma

patients with multifocal disease may benefit from RT of involved bone

compartments, we wanted to explore the feasibility and efficacy of a

multimodal intensified treatment including high-precision RT to various

numerous tumor sites (IL-RT).

Materials/Methods: All pediatric patients with metastatic disease of

Ewing sarcoma or rhabdomyosarcoma who were treated in prospective

multimodal protocols (Meta-EICESS 2007, EWING2008/CWS-guidance)

and referred to our department between 2009 and 2012 for IL-RT to all

macroscopic tumor sites as depicted by PET-CT, bone scintigraphy and

whole-body MRI were included. Treatment consisted of induction

chemotherapy (CTx) and IL-RTwith simultaneous CTx, followed by high-

dose CTx with autologous and/or allogeneic haploidentical stem cell

transplantation. RT was delivered in IMRT- and simultaneous integrated

boost-technique with daily image-guidance (tomotherapy). Acute and late

toxicity was rated according to RTOG. Survival times were calculated

from histological diagnosis to last follow-up.

Results: Between Mai 2009 and Aug 2012, 12 patients with a median age of

14 years (7-18) were treated due to stage IV Ewing sarcoma in 7 and rhab-

domyosarcoma in 5. PTVs encompassed the primary tumor site in 11 pts (total

dose 44-60Gy), 1-15 bone metastases (median 10, 40-50Gy) in 9 pts, lymph

node metastases in 7 (44-50Gy), pleural sites in 5 (localized in 4, whole ipsi-

lateral pleura in 4, 36-50Gy) and lung metastases in another 5 pts (whole lung

irradiation, 15-18Gy a 1.5Gy). The median sum of PTVs was 2762cm3 (range

1839-9407cm3). Median percentage of red bone marrow included in RT fields

according toMechanik was 34% (range 15-69%). 11 of 12 pts developed grade

4 bone marrow toxicity during simultaneous RCTx, but all treatments could be

completed with advanced supportive care (split-course schemes and stem-cell

rescue as necessary). Acute radiation-induced toxicity �grade 3 (RTOG) was

noted for liver-5pts, esophagus-2, lowerGI-2, skin-2, lung-1, urinary bladder-1,

heart-0, kidney-0. Late radiation-induced side effects �grade 3 (RTOG) were

rare, with bonemarrow-2, liver-1, kidney-1. In 1 patient, a pathological fracture

of the humerus occurred. At the time of analysis, 6/12 pts are alive with a

median follow-up of 26.5 months (10-59). 6 pts with early recurrences (1 in-

field, 2 out-of field, 3 both), died after a median of 13.4 months (10.3-17.9),

Volume 90 � Number 1S � Supplement 2014 Poster Viewing Abstracts S727

resulting in a 2- and 3-year overall survival of 50% for thewhole group and a 2-

and 3-year IF-local control rate of 64% and 42%, respectively.

Conclusions: IL-RT to all metastatic sites in multifocal pediatric sarcomas

seems to be feasible if applied with advanced RT techniques and sophis-

ticated supportive therapy including stem cell rescue.

Author Disclosure: B. Roeper: A. Employee; Resident of university

hospital. E. Research Grant; Wilhelm Sander Foundation. B. Woeller: A.

Employee; Resident of university hospital. N. Andratschke: A.

Employee; Resident of university hospital. A. Wawer: A. Employee;

Resident of university hospital. S. Kampfer: A. Employee; Physicist at

University Hospital. M. Hadjamu: A. Employee; Resident of university

hospital. I. Teichert von Luettichau: A. Employee; Resident of university

hospital. U. Thiel: A. Employee; Resident of university hospital. M.

Molls: A. Employee; Resident of university hospital. S.E.G. Burdach: A.

Employee; Resident of university hospital.

3311The Effect of Radiation Therapy in the Local Control of the Non-extremity Ewing SarcomasO. Ozkaya Akagunduz,1 S. Arun Kamer,1 B. Kececi,2 B. Kadioglu,3 H. Oniz,4

M. Kantar,5 N. Cetingul,5 D. Sabah,2 and Y. Anacak1; 1EGE University,

Faculty of Medicine, Department of Radiation Oncology, Izmir, Turkey, 2EGE

University, Faculty of Medicine, Department of Orthopedics and

Traumatology, Izmir, Turkey, 3Behcet Uz Children’s Research Hospital, Izmir,

Turkey, 4Tepecik Research Hospital, Izmir, Turkey, 5EGEUniversity, Faculty of

Medicine, Department of Pediatric Oncology, Izmir, Turkey

Purpose/Objective(s): Neoadjuvant chemotherapy followed by local ther-

apy as surgery and/or radiation therapy is the current standard for Ewing’s

sarcomas. Surgery is the treatment of choice in the cases that R0 resection is

possible - mostly cases with tumors located at extremities. R0 resection is not

possible in many non-extremity cases where radiation therapy replaces surgery

in the curative setting, or radiation therapy is used after R1-2 resections in the

adjuvant setting. We evaluated the results of radiation therapy and the prog-

nostic factors affecting the local control in non-extremity Ewing’s sarcomas.

Materials/Methods: Between 1995 and 2011, 44 patients with non-extremity

Ewing’s sarcomas were treated with radiation therapy. The median age was 17

years (4 - 41). M/F ratio was 1.1. Tumor localizations were pelvic bones in 23,

vertebras in 13 and thoracic bones in 5 and cranium in 3 patients. Tumor sizewas

�8cm in 56.8%of patients. Distant metastases were present in 19 of the patients

at the time of diagnosis (40.6%). All patients were treated with 12 weeks of

neoadjuvant chemotherapy (IE-VAC) followed by surgery + radiation therapy

(45 - 54 Gy) or radiation therapy alone (55.8 - 62 Gy). Postoperative radiation

therapy was used in 16 and radiation therapy alone was used in 28 patients.

Results: Median follow-up was 49 months (9- 195). Local failures were

developed in 7 patients (15.9%), and local control at 5 years was 81.7%. There

were 3 local failures (10.7%) in the curative setting group and 4 local failures

(25.0%) in the adjuvant group (p Z N.S). Local control rates at 5 years were

83.0% in the curative setting group and 78.0% in the adjuvant group (pZN.S).

All those patients with local failure experienced further distant metastases.

Possible prognostic factors such as age (Z <17 vs>17), tumor localization,

tumor volume (Z <8 cm vs>8 cm), M status at diagnosis (0 vs1) were not

related with local control. Overall survival at 5 years was 45%.

Conclusions: Radiation therapy, either alone or adjuvant to surgery pro-

vides local control in 80% of the non-extremity Ewing’s sarcomas and

plays an important role in the treatment.

Author Disclosure: O. Ozkaya Akagunduz: None. S. Arun Kamer:

None. B. Kececi: None. B. Kadioglu: None. H. Oniz: None. M. Kantar:

None. N. Cetingul: None. D. Sabah: None. Y. Anacak: None.

3312Survival and Toxicities Following Whole-Abdominopelvic RadiationTherapy as Part of Multimodality Treatment for Patients WithDesmoplastic Small Round Cell TumorE. Osborne,1 T.M. Briere,1 A. Hayes-Jordan,1 W.W. Huh,1 P. Anderson,2

and M.F. McAleer1; 1MD Anderson Cancer Center, Houston, TX, 2Levine

Children’s Hospital, Charlotte, NC

Purpose/Objective(s): Desmoplastic small round cell tumor (DSRCT) is

a rare, aggressive malignancy affecting adolescents and young adults. Here

we investigate survival rates and toxicities associated with multimodality

treatment including whole abdominopelvic radiation therapy (WART).

Materials/Methods: Medical records of 31 patients with DSRCT treated

from 2006 to 2013 at our institution were retrospectively reviewed. All

patients underwent multimodality therapy consisting of chemotherapy,

optimal surgical cytoreduction with hyperthermic intraperitoneal chemo-

perfusion (HIPEC), and then WART. Twenty-seven patients (87.1%)

received concurrent chemotherapy with WART. Most patients received 30

Gy in 20 fractions to the whole abdomen using intensity modulated radi-

ation therapy, and 11 patients received an integrated boost to 36 Gy to

areas of gross residual disease. Descriptive statistics were used to evaluate

local control, toxicity and survival endpoints. Toxicities were graded using

Common Terminology Criteria for Adverse Events, version 4.0.

Results: After median follow-up from WART of 16.4 mo (range, 0.3-64.5

mo), 20 patients (64.5%) had disease recurrence. Median disease free

survival from WART was 7.8 mo (range, 0.3-58.0 mo) with most re-

currences (75%) occurring within the abdomen, 40% of these in the liver.

Median abdominal failure-free survival was 8.8 mo (range 0.3-58.0 mo).

Thirty patients (96.8%) completed WART. Six patients were hospitalized

for infection during treatment, with three requiring intensive care moni-

toring. During WART, gastrointestinal toxicities were the most common

with 11 patients (35.5%) reporting grade 3 nausea or diarrhea; 91% of

these patients received concurrent chemotherapy and these symptoms

resolved in all but 9% on follow-up. Bowel obstruction (nZ 5, 16.1%) and

damage to the genitourinary system (n Z 7, 22.6%) were the most com-

mon late toxicities. There were two (6.5%) grade 5 hepatic toxicities.

Fifteen of 19 surviving patients (78.9%) had no grade 3 toxicities at one

year. Twelve patients (38.7%) died with a median overall survival from

treatment initiation of 26.7 mo (range, 9.3-78.6 mo). One patient was

without evidence of disease at 65.4 mo from diagnosis.

Conclusions: WART following chemotherapy, surgical cytoreduction and

HIPEC is an aggressive treatment approach for DSRCT patients to help

improve local control. Acute toxicities during WART are common and can

be severe, and these effects may be exacerbated by concurrent chemo-

therapy. With attentive medical oversight, most patients recovered from

acute toxicity and at one year had no severe late sequelae suggesting the

feasibility of this multimodal approach for these patients.

Author Disclosure: E. Osborne: None. T.M. Briere: None. A. Hayes-

Jordan: None. W.W. Huh: None. P. Anderson: None. M.F. McAleer:

None.

3313Stratifying Pulmonary Tumor Burden in Patients With Stage IVWilms Tumor (WT): Implications for Treatment and DiseaseOutcomeR.S. Kirkland,1 M.K. Khan,2 K. Sungjin,2 Z. Chen,3 T. Cash,4

and N. Esiashvili2; 1University of Missouri School of Medicine, Columbia,

MO, 2Emory University Winship Cancer Institute, Atlanta, GA, 3Emory

University Rollins School of Public Health, Atlanta, GA, 4Children’s

Healthcare of Atlanta, Atlanta, GA

Purpose/Objective(s): Currently, the standard treatment of pulmonary

disease in stage IV WT is not stratified by disease burden as detected on

Chest CT imaging at initial time of diagnosis. Newer strategies are

emerging to adapt indications for whole lung irradiation (WLI) based on

response to induction chemotherapy (CTX) despite sparse evidence. This

study will evaluate the role of known risk factors (risk groups, histology,

WLI, boost and metastasectomy) with lung recurrence-free survival and

overall survival in the induction CTX cohort for patients that then received

WLI irradiation with or without boost and/or underwent metastasectomy.

Materials/Methods: Thirty five pediatric patients diagnosed with stage IV

WT between 1997 and 2012 were retrospectively evaluated. All patients

had a chest CT available for radiographic review. Lung metastasis was

classified as follows: low risk (�5 nodules < 1 cm in diameter or �2

nodules < 2 cm in diameter); Intermediate risk (6-20 nodules <1 cm in