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EP-1012 FREE BREATHING GATING IS SUPERIOR TO PRONE POSITION FOR WHOLE BREAST RADIOTHERAPY
S398
ESTRO 31
Results: Median follow- up after treatment was 36months.Median age of the patients was 43 years (26-73). 90% patients were early stage and 10 % were locally advanced while 62% were node negative and 38% were node positive. Locoregional recurrence was seen in only 3.7% patients (total 3, chest wall 1) while Distant metastasis was seen in 22.9% patients. At 4.38 years Kaplan Meier estimated disease free survival was 54% and overall survival was 81%. Conclusions: Patients with TN breast cancer are not at significantly increased risk for isolated LRR at 5-years so remain appropriate candidates for breast conservation. There is increased risk of distant failure even in early stage disease associated with poor disease free survival .Targeted therapies are required in clinical trials to find new and better ways to treat it. EP-1012 FREE BREATHING GATING IS SUPERIOR TO PRONE POSITION FOR WHOLE BREAST RADIOTHERAPY C. Sweldens1, E. Van Limbergen2, C. Weltens2 1 Heilig Hart Ziekenhuis, Radiotherapy, Roeselare, Belgium 2 University Hospital Gasthuisberg, Radiotherapy, Leuven, Belgium Purpose/Objective: To compare 3 different patient positions in whole breast radiotherapy: standard supine position (without respiratory gating), supine position with respiratory gating and prone position (without respiratory gating). 3D treatment plans are generated and used to evaluate the doses to the target volumes and to the organs at risk: the heart, left artery descendens (LAD), lungs and the contralateral breast (CLB). Materials and Methods: For 34 patients treated with whole breast radiotherapy in standard supine position on the Sinmed Posiboard -2 ®, 2 additional CT scans in treatment position were obtained: 1 CT scan in supine position with free breathing gating using the Varian RPM system and 1 CT scan in prone position using the Clear Vue ® Orbital Therapy breast board. Of the 34 patients, 17 were treated for left sided breast cancer and 17 for right sided breast cancer. Breast volumes varied between 209 and 1808 cm³. On the 3 CT scans obtained for each patient, a comparable treatment plan was made and compared. Results: Dose homogeneity and target coverage was similar for the 3 techniques. The heart doses as well as the doses on the LAD were the highest in the prone plans, lower in the standard supine plans and lowest in the gated plans. The volume of the lung given 20 Gy was the highest in the standard plans, lower in the gated plans and lowest in the prone plans. Doses to the contralateral breast are highest in the prone position.
Supine standard
Supine Gating
with
V105% PTV
0,4 ± 0,3
0,2 ± 0,2
V95 % CTV
94,4 ± 2,6
93,9 ± 3,2
V95% PTV
87,3 ± 4,2
86,3 ± 4,8
Dmean (Gy) CTV
50,4 ± 0,3
50,3 ± 0,4
Dmean (Gy) PTV
49,3 ± 0,8
49,3 ± 0,8
Mean Lung Dose (Gy)
4,5 ± 1,6
3,9 ± 1,2
1,6 ± 0,7
V20 lung (%)
8,1± 3,4
6,9 ± 2,6
2,5 ± 1,3
V30 heart (%)
4,9 ± 3,6
1,3 ± 1,6
7,7 ± 5
Mean dose LAD (Gy)
28,8 ± 11,7
19,8 ± 12,2
34 ± 11,5
V 5 CLB (%)
0,03 ± 0,1
0,04 ± 0,1
0,4 ± 1,0
Prone 0,8 ± 0,9
EP-1013 VIRTUAL COMPUTER SIMULATION OF SKIN ERYTHEMA SEVERITY CATEGORIZED BY BREAST SIZE USING GENERALIZED LQ MODEL H. Sekine1, C. Kanehira2, M. Aoki2, M. Kobayashi2, S. Takagi2, K. Suzuki3 1 Jikei No.3 Hospital, Department of Radiology and Radiotherapy, Komae, Japan 2 Jikei University Hospital, Department of Radiotherapy, Tokyo, Japan 3 Saitama Medical University Hospital, Department of Radiotherapy, Moroyama, Japan Purpose/Objective: The purpose of this study is to display skin erythema severity categorized by breast size after breast conserving therapy using generalized LQ (GLQ) model. GLQ model includes not only interfraction interval, but also time after irradiation. This model can express both division cell death and apoptotic cell death. Materials and Methods: One hundred and nineteen of early breast cancer patients (31; large size breast, 51; middle size breast, and 37; small size breast) after breast conserving surgery, who were planned post-operative radiotherapy, were enrolled to this study. Radiotherapy was delivered tangentially non-coplanar method in 2 Gy/fr with 4 -6MV photon beams, 5 fr/w until 50 Gy, and some patients were given boost irradiation. Quantitative measurements of radiation induced skin erythema have been detected using by reflectance spectrophotometer (CM-2500d, KONIKA-MINOLTA, Tokyo, Japan) every week until the end of the radiation course. Follow up time after the therapy is 2weeks, 1 month and every three months thereafter. Measured color is expressed by 3-dimentional factors using L*a*b*: L* indicates lightness and a* and b* are chromaticity coordinates. For the computer simulation, L*a*b* values were converted to HSB (Hue, Saturation, and Brightness) values. The coefficients of α, β, and T1/2 (half response time) are estimated by non-linear regression analysis of dose-effect plots of H, S, and B, respectively. By the assumption that skin erythema will repair until steady state, repair half time of skin erythema is obtained by iterative calculation. Accumulated doses were projected on time scale. GLQ models of each H, S, and B parameters according to breast size simulate the appearance of skin erythema during and after irradiation on the 3D breast graphic model. Software used in this study is Mathematica ver. 8 on Macintosh OS10.6. Results: Because S was increased according to dose accumulation, nonlinear regression curve of 1/S produced by fitting of inverted S data, and re-inversion of this curve induced regression curve of S. Nonlinear regression coefficients of alfa/beta of each breast sizes were shown as follows (Small: 4.7,4.5,2.9, Middle: 4.9,3.8,2.3, and Large: 3.9,2.9,2.9), and doubling time = 15, T1/2=12, Label Index=1%. Graphical simulation of skin erythema will be shown on the display. Conclusions: GLQ model can analyze Time-Dose Effect of fractionated irradiation along time scale. By this model, visual simulation of rise and fall of skin erythema severity categorized by breast size during and after irradiation could be shown on display.
93,5 ± 2 86,6 4,3 50,4 0,4 49,5 0,7
± ± ±
Conclusions: In this study population, coverage of the CTV and PTV was equal for the 3 tested techniques. Prone position is an advantage for the doses to the lungs however has a negative effect on doses to the heart, LAD and the contralateral breast. Gating provides a good coverage of the target volumes as well as low doses to the heart, the lung and the contralateral breast. From the 3 compared techniques, free breathing gating in supine position scores best on all relevant dose parameters: decreased doses to the organs at risk with comparable dose homogeneity in the target volume.
EP-1014 HYPOFRACTIONATED ACCELERATED RADIOTHERAPY BY SIMULTANEOUS INTEGRATED BOOST FOR HIGH RISK BREAST CANCER PATIENTS N. Rodríguez Ibarria1, A. Cabezón1, L. García1, A. Riveros1, M. Lloret1, I. Ramírez1, L.A. Henríquez-Hernández1, A. Valenciano1, P.C. Lara1 1 Hospital Universitario de Gran Canaria Dr. Negrín and Instituto Canario de Investigación del Cáncer (ICIC), Radiation Oncology, Las Palmas de Gran Canaria Ca, Spain Purpose/Objective: Hypofractionated Accelerated Radiotherapy has proved to be useful in early breast tumours, but little is known when risk features as close or affected margins make necesary to increase final doses in the tumour bed. The purpose of the present study was to explore the feasibility in terms of local control and toxicity of a hypofractionated accelerated scheme by SIB in a time shorter than the standard 7 weeks in unselected conservatively treated high risk breast cancer patients. Materials and Methods: From January 2008 to December 2010, 204 patients were prospectively included in the present study. Mean age was 53,23+/-12,58, median 52,50 range 24-88, 75% menopausal. Most of the cases were DIC (88,3%), T1(73%), N0 (63,2%), stage 1(46,8%) and RE+ 81,7% & RP+ 72,9%. Centinel Node Biopsy was performed in all cases. Conservative surgery was followed in 110 cases (58%) by axillary dissection (when positive node at centinel biopsy). Most of the patients (133) recieved adjuvant chemotherapy and hormotherapy. All cases were considered for a boost on the tumour bed, either by close or affected margins, or high risk cases. Radiotherapy was
ESTRO 31
Results: Median follow- up after treatment was 36months.Median age of the patients was 43 years (26-73). 90% patients were early stage and 10 % were locally advanced while 62% were node negative and 38% were node positive. Locoregional recurrence was seen in only 3.7% patients (total 3, chest wall 1) while Distant metastasis was seen in 22.9% patients. At 4.38 years Kaplan Meier estimated disease free survival was 54% and overall survival was 81%. Conclusions: Patients with TN breast cancer are not at significantly increased risk for isolated LRR at 5-years so remain appropriate candidates for breast conservation. There is increased risk of distant failure even in early stage disease associated with poor disease free survival .Targeted therapies are required in clinical trials to find new and better ways to treat it. EP-1012 FREE BREATHING GATING IS SUPERIOR TO PRONE POSITION FOR WHOLE BREAST RADIOTHERAPY C. Sweldens1, E. Van Limbergen2, C. Weltens2 1 Heilig Hart Ziekenhuis, Radiotherapy, Roeselare, Belgium 2 University Hospital Gasthuisberg, Radiotherapy, Leuven, Belgium Purpose/Objective: To compare 3 different patient positions in whole breast radiotherapy: standard supine position (without respiratory gating), supine position with respiratory gating and prone position (without respiratory gating). 3D treatment plans are generated and used to evaluate the doses to the target volumes and to the organs at risk: the heart, left artery descendens (LAD), lungs and the contralateral breast (CLB). Materials and Methods: For 34 patients treated with whole breast radiotherapy in standard supine position on the Sinmed Posiboard -2 ®, 2 additional CT scans in treatment position were obtained: 1 CT scan in supine position with free breathing gating using the Varian RPM system and 1 CT scan in prone position using the Clear Vue ® Orbital Therapy breast board. Of the 34 patients, 17 were treated for left sided breast cancer and 17 for right sided breast cancer. Breast volumes varied between 209 and 1808 cm³. On the 3 CT scans obtained for each patient, a comparable treatment plan was made and compared. Results: Dose homogeneity and target coverage was similar for the 3 techniques. The heart doses as well as the doses on the LAD were the highest in the prone plans, lower in the standard supine plans and lowest in the gated plans. The volume of the lung given 20 Gy was the highest in the standard plans, lower in the gated plans and lowest in the prone plans. Doses to the contralateral breast are highest in the prone position.
Supine standard
Supine Gating
with
V105% PTV
0,4 ± 0,3
0,2 ± 0,2
V95 % CTV
94,4 ± 2,6
93,9 ± 3,2
V95% PTV
87,3 ± 4,2
86,3 ± 4,8
Dmean (Gy) CTV
50,4 ± 0,3
50,3 ± 0,4
Dmean (Gy) PTV
49,3 ± 0,8
49,3 ± 0,8
Mean Lung Dose (Gy)
4,5 ± 1,6
3,9 ± 1,2
1,6 ± 0,7
V20 lung (%)
8,1± 3,4
6,9 ± 2,6
2,5 ± 1,3
V30 heart (%)
4,9 ± 3,6
1,3 ± 1,6
7,7 ± 5
Mean dose LAD (Gy)
28,8 ± 11,7
19,8 ± 12,2
34 ± 11,5
V 5 CLB (%)
0,03 ± 0,1
0,04 ± 0,1
0,4 ± 1,0
Prone 0,8 ± 0,9
EP-1013 VIRTUAL COMPUTER SIMULATION OF SKIN ERYTHEMA SEVERITY CATEGORIZED BY BREAST SIZE USING GENERALIZED LQ MODEL H. Sekine1, C. Kanehira2, M. Aoki2, M. Kobayashi2, S. Takagi2, K. Suzuki3 1 Jikei No.3 Hospital, Department of Radiology and Radiotherapy, Komae, Japan 2 Jikei University Hospital, Department of Radiotherapy, Tokyo, Japan 3 Saitama Medical University Hospital, Department of Radiotherapy, Moroyama, Japan Purpose/Objective: The purpose of this study is to display skin erythema severity categorized by breast size after breast conserving therapy using generalized LQ (GLQ) model. GLQ model includes not only interfraction interval, but also time after irradiation. This model can express both division cell death and apoptotic cell death. Materials and Methods: One hundred and nineteen of early breast cancer patients (31; large size breast, 51; middle size breast, and 37; small size breast) after breast conserving surgery, who were planned post-operative radiotherapy, were enrolled to this study. Radiotherapy was delivered tangentially non-coplanar method in 2 Gy/fr with 4 -6MV photon beams, 5 fr/w until 50 Gy, and some patients were given boost irradiation. Quantitative measurements of radiation induced skin erythema have been detected using by reflectance spectrophotometer (CM-2500d, KONIKA-MINOLTA, Tokyo, Japan) every week until the end of the radiation course. Follow up time after the therapy is 2weeks, 1 month and every three months thereafter. Measured color is expressed by 3-dimentional factors using L*a*b*: L* indicates lightness and a* and b* are chromaticity coordinates. For the computer simulation, L*a*b* values were converted to HSB (Hue, Saturation, and Brightness) values. The coefficients of α, β, and T1/2 (half response time) are estimated by non-linear regression analysis of dose-effect plots of H, S, and B, respectively. By the assumption that skin erythema will repair until steady state, repair half time of skin erythema is obtained by iterative calculation. Accumulated doses were projected on time scale. GLQ models of each H, S, and B parameters according to breast size simulate the appearance of skin erythema during and after irradiation on the 3D breast graphic model. Software used in this study is Mathematica ver. 8 on Macintosh OS10.6. Results: Because S was increased according to dose accumulation, nonlinear regression curve of 1/S produced by fitting of inverted S data, and re-inversion of this curve induced regression curve of S. Nonlinear regression coefficients of alfa/beta of each breast sizes were shown as follows (Small: 4.7,4.5,2.9, Middle: 4.9,3.8,2.3, and Large: 3.9,2.9,2.9), and doubling time = 15, T1/2=12, Label Index=1%. Graphical simulation of skin erythema will be shown on the display. Conclusions: GLQ model can analyze Time-Dose Effect of fractionated irradiation along time scale. By this model, visual simulation of rise and fall of skin erythema severity categorized by breast size during and after irradiation could be shown on display.
93,5 ± 2 86,6 4,3 50,4 0,4 49,5 0,7
± ± ±
Conclusions: In this study population, coverage of the CTV and PTV was equal for the 3 tested techniques. Prone position is an advantage for the doses to the lungs however has a negative effect on doses to the heart, LAD and the contralateral breast. Gating provides a good coverage of the target volumes as well as low doses to the heart, the lung and the contralateral breast. From the 3 compared techniques, free breathing gating in supine position scores best on all relevant dose parameters: decreased doses to the organs at risk with comparable dose homogeneity in the target volume.
EP-1014 HYPOFRACTIONATED ACCELERATED RADIOTHERAPY BY SIMULTANEOUS INTEGRATED BOOST FOR HIGH RISK BREAST CANCER PATIENTS N. Rodríguez Ibarria1, A. Cabezón1, L. García1, A. Riveros1, M. Lloret1, I. Ramírez1, L.A. Henríquez-Hernández1, A. Valenciano1, P.C. Lara1 1 Hospital Universitario de Gran Canaria Dr. Negrín and Instituto Canario de Investigación del Cáncer (ICIC), Radiation Oncology, Las Palmas de Gran Canaria Ca, Spain Purpose/Objective: Hypofractionated Accelerated Radiotherapy has proved to be useful in early breast tumours, but little is known when risk features as close or affected margins make necesary to increase final doses in the tumour bed. The purpose of the present study was to explore the feasibility in terms of local control and toxicity of a hypofractionated accelerated scheme by SIB in a time shorter than the standard 7 weeks in unselected conservatively treated high risk breast cancer patients. Materials and Methods: From January 2008 to December 2010, 204 patients were prospectively included in the present study. Mean age was 53,23+/-12,58, median 52,50 range 24-88, 75% menopausal. Most of the cases were DIC (88,3%), T1(73%), N0 (63,2%), stage 1(46,8%) and RE+ 81,7% & RP+ 72,9%. Centinel Node Biopsy was performed in all cases. Conservative surgery was followed in 110 cases (58%) by axillary dissection (when positive node at centinel biopsy). Most of the patients (133) recieved adjuvant chemotherapy and hormotherapy. All cases were considered for a boost on the tumour bed, either by close or affected margins, or high risk cases. Radiotherapy was