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P2.05-038 Initial Clinical Experience of VMAT-SBRT with Flattening-Filter-Free Techniques in the University of Tokyo Hospital
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(p¼0.008) or AJCC stage (p¼0.036). With univariate analysis, AJCC stage (p<0.001), ratio of GTV to CTV (p ¼ 0.005), tumor response to 50Gy of TRT (p ¼ 0.004), the duration from the start date of induction chemotherapy to the end of TRT (SER, p ¼ 0.003), and PCI (p ¼ 0.035) were statistically significant predictor of OS. Multivariate Cox regression demonstrated that AJCC stage (p<0.001) and SER (p ¼ 0.007) only were significant. In patients with SER <80days & CR to 50Gy TRT, median survival was not yet reached until now. Conclusion: LSCLC patients who showed CR to 50 Gy of TRT and completed TRT within 80days represented the outstanding survival outcomes. Based on these results, we need the further study evaluating whether dose escalation more than 50 Gy is promising for survival improvement in patients with CR at the time of 50 Gy of early TRT and chemotherapy.
P2.05-038 Initial Clinical Experience of VMAT-SBRT with Flattening-Filter-Free Techniques in the University of Tokyo Hospital Topic: RT Techniques Shuri Aoki, Hideomi Yamashita, Akihiro Haga, Kanabu Nawa, Keiichi Nakagawa Department of Radiology, University of Tokyo Hospital, Tokyo/Japan Background: Stereotactic body therapy (SBRT) has been widely used as a safe and effective treatment method for primary or metastatic lung tumors. Among new techniques for SBRT, utilization of flattening-filter-free (FFF) beams allows more rapid delivery of treatment doses and may enable to improve clinical stability and comfort. FFF techniques have been adopted to our volumetric modulated arc therapy (VMAT)-SBRT system since 2013. We evaluated the safety and availability of VMAT-SBRT using FFF techniques in a clinical field of treatment of primary and metastatic lung tumors. Methods: A total of 62 lung VMAT-SBRT cases treated at our institution using an Elekta-synergy system from 11/ 2013 to 11/2015 were reviewed. SBRT plans using VMAT with single partial arc (220 degree) were optimized in the pinnacle3 treatment planning system with inhomogeneity correction. We targeted at 48 cases with 1) one or two targets; 2) tumor diameter<40mm; 3) dose prescription¼ 55Gy/4Fr for peripheral lesions or 56Gy/7Fr for central lesions (PTV-D95); 4) image diagnostic approaches performed after treatment. In each prescription dose, We compared between two groups (flattening filter; FF vs. FFF) in total monitor units (MUs),
Journal of Thoracic Oncology
Vol. 12 No. 1S
treatment time, dose for tumors (ITV-D5, D50, D98, etc.), dose for lungs (V5,V20,MLD etc.), local recurrence, radiation pneumonitis, the other adverse events. Results: Before November 2014, 24 patients (peripheral: central¼19:5) were treated with conventional FF VMAT, and remaining 24 patients (peripheral: central¼18:6) with FFF VMAT. There were T1 primary lung tumors in 29 patients (FF:FFF¼ 14:15) including 8 GGOs, T2- in 10 patients (5:5), and metastatic tumors in 9 patients (5:4). In the both prescription dose, significant differences were found in the average treatment times; FF: FFF¼3.65:1.45(sec) for 55Gy/4Fr, 2.28:1.26(sec) for 56Gy/7Fr respectively, while no significant difference in the mean total MUs; FF:FFF respectively, while no significant difference in the mean total MU values; FF:FFF¼ 2128 (range, 1099-2817):2100 (range, 1505-2343). The dose for tumors and lungs did not show significant differences between two groups.Local recurrence occurred in 3 patients (FF: FFF¼1:2), Grade2 radiation pneumonitis occurred in 5 cases (FF: FFF¼3:2), and the other adverse events were within an allowance compared with past reports. Conclusion: The VMAT-SBRT using FFF techniques could shorten the treatment time of lungSBRT keeping the high local control rate and the low toxicity in the clinical field. Keywords: flattening filter-free techniques, treatment time, Stereotactic body radiation therapy, lung cancer
P2.05-039 Assessment of Lung Tumor Motion Comparing 4DCT, 4DCBCT and Motion of Implanted Beacons during Imaging and Irradiation Topic: RT Techniques Elisabeth Steiner,1 Chun-Chien Shieh,1 Vincent Caillet,2 Nicholas Hardcastle,2 Carol Haddad,2 Paul Keall,1 Thomas Eade,2 Jeremy Booth2 1Clinical Medical School - Central, Radiations Physics Laboratory, University of Sydney, Camperdown/NSW/Australia, 2Northern Sydney Cancer Centre, Royal North Shore Hospital, St Leonards/NSW/ Australia Background: Moving lung tumors exceeding the observed motion from planning 4D computed tomography (4DCT) can result in reduced dose coverage in stereotactic ablative body radiation therapy (SABR). 4D cone-beam CT (4DCBCT) facilitates verification of tumor
(p¼0.008) or AJCC stage (p¼0.036). With univariate analysis, AJCC stage (p<0.001), ratio of GTV to CTV (p ¼ 0.005), tumor response to 50Gy of TRT (p ¼ 0.004), the duration from the start date of induction chemotherapy to the end of TRT (SER, p ¼ 0.003), and PCI (p ¼ 0.035) were statistically significant predictor of OS. Multivariate Cox regression demonstrated that AJCC stage (p<0.001) and SER (p ¼ 0.007) only were significant. In patients with SER <80days & CR to 50Gy TRT, median survival was not yet reached until now. Conclusion: LSCLC patients who showed CR to 50 Gy of TRT and completed TRT within 80days represented the outstanding survival outcomes. Based on these results, we need the further study evaluating whether dose escalation more than 50 Gy is promising for survival improvement in patients with CR at the time of 50 Gy of early TRT and chemotherapy.
P2.05-038 Initial Clinical Experience of VMAT-SBRT with Flattening-Filter-Free Techniques in the University of Tokyo Hospital Topic: RT Techniques Shuri Aoki, Hideomi Yamashita, Akihiro Haga, Kanabu Nawa, Keiichi Nakagawa Department of Radiology, University of Tokyo Hospital, Tokyo/Japan Background: Stereotactic body therapy (SBRT) has been widely used as a safe and effective treatment method for primary or metastatic lung tumors. Among new techniques for SBRT, utilization of flattening-filter-free (FFF) beams allows more rapid delivery of treatment doses and may enable to improve clinical stability and comfort. FFF techniques have been adopted to our volumetric modulated arc therapy (VMAT)-SBRT system since 2013. We evaluated the safety and availability of VMAT-SBRT using FFF techniques in a clinical field of treatment of primary and metastatic lung tumors. Methods: A total of 62 lung VMAT-SBRT cases treated at our institution using an Elekta-synergy system from 11/ 2013 to 11/2015 were reviewed. SBRT plans using VMAT with single partial arc (220 degree) were optimized in the pinnacle3 treatment planning system with inhomogeneity correction. We targeted at 48 cases with 1) one or two targets; 2) tumor diameter<40mm; 3) dose prescription¼ 55Gy/4Fr for peripheral lesions or 56Gy/7Fr for central lesions (PTV-D95); 4) image diagnostic approaches performed after treatment. In each prescription dose, We compared between two groups (flattening filter; FF vs. FFF) in total monitor units (MUs),
Journal of Thoracic Oncology
Vol. 12 No. 1S
treatment time, dose for tumors (ITV-D5, D50, D98, etc.), dose for lungs (V5,V20,MLD etc.), local recurrence, radiation pneumonitis, the other adverse events. Results: Before November 2014, 24 patients (peripheral: central¼19:5) were treated with conventional FF VMAT, and remaining 24 patients (peripheral: central¼18:6) with FFF VMAT. There were T1 primary lung tumors in 29 patients (FF:FFF¼ 14:15) including 8 GGOs, T2- in 10 patients (5:5), and metastatic tumors in 9 patients (5:4). In the both prescription dose, significant differences were found in the average treatment times; FF: FFF¼3.65:1.45(sec) for 55Gy/4Fr, 2.28:1.26(sec) for 56Gy/7Fr respectively, while no significant difference in the mean total MUs; FF:FFF respectively, while no significant difference in the mean total MU values; FF:FFF¼ 2128 (range, 1099-2817):2100 (range, 1505-2343). The dose for tumors and lungs did not show significant differences between two groups.Local recurrence occurred in 3 patients (FF: FFF¼1:2), Grade2 radiation pneumonitis occurred in 5 cases (FF: FFF¼3:2), and the other adverse events were within an allowance compared with past reports. Conclusion: The VMAT-SBRT using FFF techniques could shorten the treatment time of lungSBRT keeping the high local control rate and the low toxicity in the clinical field. Keywords: flattening filter-free techniques, treatment time, Stereotactic body radiation therapy, lung cancer
P2.05-039 Assessment of Lung Tumor Motion Comparing 4DCT, 4DCBCT and Motion of Implanted Beacons during Imaging and Irradiation Topic: RT Techniques Elisabeth Steiner,1 Chun-Chien Shieh,1 Vincent Caillet,2 Nicholas Hardcastle,2 Carol Haddad,2 Paul Keall,1 Thomas Eade,2 Jeremy Booth2 1Clinical Medical School - Central, Radiations Physics Laboratory, University of Sydney, Camperdown/NSW/Australia, 2Northern Sydney Cancer Centre, Royal North Shore Hospital, St Leonards/NSW/ Australia Background: Moving lung tumors exceeding the observed motion from planning 4D computed tomography (4DCT) can result in reduced dose coverage in stereotactic ablative body radiation therapy (SABR). 4D cone-beam CT (4DCBCT) facilitates verification of tumor