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EP-1279 RESPONSE OF RETROPERITONEAL SARCOMAS TO PRE-OPERATIVE RADIOTHERAPY
ESTRO 31
oldest patient rejected all treatments. The other 6 patients had unresectable disease and were treated by RT with curative intent with chemotherapy or interleukin-2 immunotherapy. In this study, 6 patients were analyzed. We used 6-12 MeV electron beams with a 1 cm bolus, and the energy was selected depending on the depth of disease measured by CT or MRI. The total dose was 63-72.5 Gy (median 70 Gy) in 26-29 fractions, and the fraction size was 2.5 Gy in principle. Four of the 6 patients were given 70 Gy in 28 fractions or more. Overall survival (OS) and distant metastasis-free survival (DMFS) of the 6 patients treated by RT were calculated from the date of diagnosis. Toxicities following RT were graded using the Common Toxicity Criteria for Adverse Events v4.0. Results: For all 6 patients treated by RT, the median follow-up was 25 months (range 4-46). That of survivors was 36 months (range 4-46). Only 1 patient died from distant metastases, 14 months after the initial treatment. For all 6 patients, the median OS was 25 months (range 4-46). Complete response rate was 100% and no patient suffered local relapse. DM occurred in 5 patients, at a median of 13 months (1-y DMFS, 67 %; 2-y DMFS, 33 %). The lung was the most common site of DM (n = 3). The other sites of DM were the liver, brain and cervical lymph (n = 1, each). Acute dermatitis was grade 2 in 2 patients (33%) and grade 3 in 4 (67%). No patient developed grade 3 or 4 dermatitis. Conclusions: Hypofractionated high-dose RT with electron beams was feasible and achieved excellent local control of angiosarcoma for older patients compared with previous reports. EP-1278 EXTRACORPORAL BONE IRRADIATION (ECI) DURING OPERATION OF SARCOMAS H. Petermann1, A.H. Krieg2, F.B. Zimmermann1, L. Plasswilm3, M.W. Gross1 1 University Hospital Basel, Radio-Oncology, Basel, Switzerland 2 University Childrens Hospital Basel, Orthopaedic Dept., Basel, Switzerland 3 Kantonsspital, Radio-Oncology, St. Gallen, Switzerland Purpose/Objective: A reconstruction technique of sarcoma involved bone tissue with 1) explantation, 2) irradiation of explanted bone with 50 Gy single dose and 3) reimplantation of the irradiated autografts was established in 2006. A save, fast and homogeneous irradiation technique is presented. Materials and Methods: Resected bone is packed fourfold to prevent infection with each sheath being evacuated to avoid air cavities. Sample is positioned in a small water phantom set on the linac couch. Position of the package inside the water column is guaranteed by a plastic foil attached to the ground of the basin. Irradiation is done with a preconfigured water phantom plan by laterally opposed beams with 10 MV photons. Cone beam CTs before and after irradiation were used to verify bone position and to calculate 3-D-dose distribution, respectively. Results: Up to now 10 patients had been treated with ECI. Setup of the water phantom on the linac and fixation of the sample takes 15 min, irradiation including cone beam CTs additional 25 min. Independent of its previously unknown shape, the bone can be placed well inside the homogeneous part of the irradiated volume. Dose distribution showed an inhomogeneity of less than +/-3% even in large samples. Residual air cavities inside the evacuated sheath lead to an increase of dose inhomogeneities not exceeding 95% to 107% of the prescribed dose. Tumor control rate was excellent. Conclusions: Our procedure for extracorporal irradiation is safe, moderately time consuming and delivers excellent clinical results. EP-1279 RESPONSE OF RETROPERITONEAL SARCOMAS TO PRE-OPERATIVE RADIOTHERAPY P. Wong1, C. Dickie1, D. Lee1, P. Chung1, B. O'Sullivan1, C. Swallow2, R. Gladdy2, C. Catton1 1 Princess Margaret Hospital, Radiation Oncology, Toronto, Canada 2 Mount Sinai Hospital, Surgical Oncology, Toronto, Canada Purpose/Objective: Pre-operative radiotherapy (RT) for retroperitoneal sarcomas (RPS) benefit from improved tumor targeting and normal tissue avoidance through displacement of normal tissues away from the RT field. However, the efficacy of pre-operative radiotherapy is yet to be examined and disease progression during radiotherapy may reduce the resectability of RPS. This study examines the response of RPS during RT using cone beam CTs (CBCT) acquired daily during RT.
S487
Materials and Methods: Between January 2007 and December 2010, patients treated radically or pre-operatively using IMRT with daily CBCT for RPS were identified. Patients were excluded from the analysis if there was 1) incomplete imaging of the tumors on CBCT, 2) pre-RT chemotherapy or 3) difficulty in co-registering the simulation CT with the CBCTs. Nineteen patients remained for analysis. One CBCT per week of treatment was contoured and analyzed to quantify the volumetric changes of the gross tumor volumes (GTVs). A total of 118 CBCTs were contoured and analyzed using student’s t-test. Results: There were 4 male and 15 female patients with a median age of 61 at diagnosis. Fourteen of the tumors were high grade. The 3 most common histologies were liposarcomas (42%), leiomyosarcomas (21%) and undifferentiated pleomorphic sarcoma (21%). Radiotherapy (median dose = 50 Gy; range: 14.4-50.4 Gy) was delivered to tumors with a median volume of 417 cc (range: 61-3516 cc). The GTVs at the final week of radiotherapy was smaller in 14 of the 19 patients. As compared to the GTVs measured on the first CBCT, the mean GTVs regressed by -3.15% (p=0.032), -2.19% (p=0.28), 1.21% (p=0.32), 1.94% (p=0.21) and 5.77% (p=0.0013) during the subsequent 5 weeks of radiotherapy (see figure). All 15 patients who were planned to undergo surgery following radiotherapy underwent surgery. R0 surgeries were achieved in 3/5 of the tumors that grew and 5/10 of those that shrunk during radiotherapy (see table). The remaining resections resulted in microscopically positive margins (R1). Conclusions: Volumetric measurements of RPS during RT indicated that GTVs typically progress during the first 2 weeks of RT before stabilizing and regressing. In this study, 76% of RPS responded or were stabilized by radiotherapy. Pre-operative radiotherapy did not seem to adversely affect the quality of surgical margins. Variables
Responding Tumors (n=14) Age at diagnosis (Median) 66.5 Gender (F:M) 10:4 Tumor Grade Low 2 High 9 N/A 3 Tumor Histology Liposarcoma 6 Leiomyosarcoma 2 Undifferentiated 3 Other 3 Median GTV at simulation 909 (61-3516) cc (Range) Median RT dose 50 Gy Median duration of RT from 47 (30-62) days simulation date (Range) Surgery Yes 10 No 4 R0 5 R1 5
ELECTRONIC POSTER: STEREOTACTIC RT
Progressing Tumors (n=5) 56 5:0 0 5 0 2 2 1 0 267 (70-3097) cc 50 Gy 47 (43-65) days 5 0 3 2
CLINICAL
All Tumors (n=19) 61 15:4 2 14 3 8 4 4 3 417 (61-3516) cc 50 Gy 47 (30-65) days 15 4 8 7
TRACK:
EP-1280 ELECTIVE WBRT AFTER SRS OR SRT FOR OLIGOMETASTATIC BRAIN TUMOR? A SINGLE INSTITUTION EXPERIENCE A. Argenone1, I. Cusano2, C. Moriello2, E. Spacagna2, A. Viscusi2, T. Pironti2 1 Azienda Ospedaliera Universitaria Senese, Department of Radiotherapy, Siena, Italy 2 Azienda Ospedaliera G. Rummo, Department of Radiotherapy, Benevento, Italy
oldest patient rejected all treatments. The other 6 patients had unresectable disease and were treated by RT with curative intent with chemotherapy or interleukin-2 immunotherapy. In this study, 6 patients were analyzed. We used 6-12 MeV electron beams with a 1 cm bolus, and the energy was selected depending on the depth of disease measured by CT or MRI. The total dose was 63-72.5 Gy (median 70 Gy) in 26-29 fractions, and the fraction size was 2.5 Gy in principle. Four of the 6 patients were given 70 Gy in 28 fractions or more. Overall survival (OS) and distant metastasis-free survival (DMFS) of the 6 patients treated by RT were calculated from the date of diagnosis. Toxicities following RT were graded using the Common Toxicity Criteria for Adverse Events v4.0. Results: For all 6 patients treated by RT, the median follow-up was 25 months (range 4-46). That of survivors was 36 months (range 4-46). Only 1 patient died from distant metastases, 14 months after the initial treatment. For all 6 patients, the median OS was 25 months (range 4-46). Complete response rate was 100% and no patient suffered local relapse. DM occurred in 5 patients, at a median of 13 months (1-y DMFS, 67 %; 2-y DMFS, 33 %). The lung was the most common site of DM (n = 3). The other sites of DM were the liver, brain and cervical lymph (n = 1, each). Acute dermatitis was grade 2 in 2 patients (33%) and grade 3 in 4 (67%). No patient developed grade 3 or 4 dermatitis. Conclusions: Hypofractionated high-dose RT with electron beams was feasible and achieved excellent local control of angiosarcoma for older patients compared with previous reports. EP-1278 EXTRACORPORAL BONE IRRADIATION (ECI) DURING OPERATION OF SARCOMAS H. Petermann1, A.H. Krieg2, F.B. Zimmermann1, L. Plasswilm3, M.W. Gross1 1 University Hospital Basel, Radio-Oncology, Basel, Switzerland 2 University Childrens Hospital Basel, Orthopaedic Dept., Basel, Switzerland 3 Kantonsspital, Radio-Oncology, St. Gallen, Switzerland Purpose/Objective: A reconstruction technique of sarcoma involved bone tissue with 1) explantation, 2) irradiation of explanted bone with 50 Gy single dose and 3) reimplantation of the irradiated autografts was established in 2006. A save, fast and homogeneous irradiation technique is presented. Materials and Methods: Resected bone is packed fourfold to prevent infection with each sheath being evacuated to avoid air cavities. Sample is positioned in a small water phantom set on the linac couch. Position of the package inside the water column is guaranteed by a plastic foil attached to the ground of the basin. Irradiation is done with a preconfigured water phantom plan by laterally opposed beams with 10 MV photons. Cone beam CTs before and after irradiation were used to verify bone position and to calculate 3-D-dose distribution, respectively. Results: Up to now 10 patients had been treated with ECI. Setup of the water phantom on the linac and fixation of the sample takes 15 min, irradiation including cone beam CTs additional 25 min. Independent of its previously unknown shape, the bone can be placed well inside the homogeneous part of the irradiated volume. Dose distribution showed an inhomogeneity of less than +/-3% even in large samples. Residual air cavities inside the evacuated sheath lead to an increase of dose inhomogeneities not exceeding 95% to 107% of the prescribed dose. Tumor control rate was excellent. Conclusions: Our procedure for extracorporal irradiation is safe, moderately time consuming and delivers excellent clinical results. EP-1279 RESPONSE OF RETROPERITONEAL SARCOMAS TO PRE-OPERATIVE RADIOTHERAPY P. Wong1, C. Dickie1, D. Lee1, P. Chung1, B. O'Sullivan1, C. Swallow2, R. Gladdy2, C. Catton1 1 Princess Margaret Hospital, Radiation Oncology, Toronto, Canada 2 Mount Sinai Hospital, Surgical Oncology, Toronto, Canada Purpose/Objective: Pre-operative radiotherapy (RT) for retroperitoneal sarcomas (RPS) benefit from improved tumor targeting and normal tissue avoidance through displacement of normal tissues away from the RT field. However, the efficacy of pre-operative radiotherapy is yet to be examined and disease progression during radiotherapy may reduce the resectability of RPS. This study examines the response of RPS during RT using cone beam CTs (CBCT) acquired daily during RT.
S487
Materials and Methods: Between January 2007 and December 2010, patients treated radically or pre-operatively using IMRT with daily CBCT for RPS were identified. Patients were excluded from the analysis if there was 1) incomplete imaging of the tumors on CBCT, 2) pre-RT chemotherapy or 3) difficulty in co-registering the simulation CT with the CBCTs. Nineteen patients remained for analysis. One CBCT per week of treatment was contoured and analyzed to quantify the volumetric changes of the gross tumor volumes (GTVs). A total of 118 CBCTs were contoured and analyzed using student’s t-test. Results: There were 4 male and 15 female patients with a median age of 61 at diagnosis. Fourteen of the tumors were high grade. The 3 most common histologies were liposarcomas (42%), leiomyosarcomas (21%) and undifferentiated pleomorphic sarcoma (21%). Radiotherapy (median dose = 50 Gy; range: 14.4-50.4 Gy) was delivered to tumors with a median volume of 417 cc (range: 61-3516 cc). The GTVs at the final week of radiotherapy was smaller in 14 of the 19 patients. As compared to the GTVs measured on the first CBCT, the mean GTVs regressed by -3.15% (p=0.032), -2.19% (p=0.28), 1.21% (p=0.32), 1.94% (p=0.21) and 5.77% (p=0.0013) during the subsequent 5 weeks of radiotherapy (see figure). All 15 patients who were planned to undergo surgery following radiotherapy underwent surgery. R0 surgeries were achieved in 3/5 of the tumors that grew and 5/10 of those that shrunk during radiotherapy (see table). The remaining resections resulted in microscopically positive margins (R1). Conclusions: Volumetric measurements of RPS during RT indicated that GTVs typically progress during the first 2 weeks of RT before stabilizing and regressing. In this study, 76% of RPS responded or were stabilized by radiotherapy. Pre-operative radiotherapy did not seem to adversely affect the quality of surgical margins. Variables
Responding Tumors (n=14) Age at diagnosis (Median) 66.5 Gender (F:M) 10:4 Tumor Grade Low 2 High 9 N/A 3 Tumor Histology Liposarcoma 6 Leiomyosarcoma 2 Undifferentiated 3 Other 3 Median GTV at simulation 909 (61-3516) cc (Range) Median RT dose 50 Gy Median duration of RT from 47 (30-62) days simulation date (Range) Surgery Yes 10 No 4 R0 5 R1 5
ELECTRONIC POSTER: STEREOTACTIC RT
Progressing Tumors (n=5) 56 5:0 0 5 0 2 2 1 0 267 (70-3097) cc 50 Gy 47 (43-65) days 5 0 3 2
CLINICAL
All Tumors (n=19) 61 15:4 2 14 3 8 4 4 3 417 (61-3516) cc 50 Gy 47 (30-65) days 15 4 8 7
TRACK:
EP-1280 ELECTIVE WBRT AFTER SRS OR SRT FOR OLIGOMETASTATIC BRAIN TUMOR? A SINGLE INSTITUTION EXPERIENCE A. Argenone1, I. Cusano2, C. Moriello2, E. Spacagna2, A. Viscusi2, T. Pironti2 1 Azienda Ospedaliera Universitaria Senese, Department of Radiotherapy, Siena, Italy 2 Azienda Ospedaliera G. Rummo, Department of Radiotherapy, Benevento, Italy