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H. Yamashita



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    OA12 - SBRT and Other Issues in Early Stage NSCLC (ID 383)

    • Event: WCLC 2016
    • Type: Oral Session
    • Track: Early Stage NSCLC
    • Presentations: 1
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      OA12.02 - Excellent Survival Achieved by Stereotactic Body Radiotherapy for Medically Operable and Young (< 75 Years) Patients with Stage I Lung Cancer (ID 5019)

      11:10 - 11:20  |  Author(s): H. Yamashita

      • Abstract
      • Presentation
      • Slides

      Background:
      Stereotactic body radiotherapy (SBRT) has been sometimes used as a curative treatment for both of medically operable patients with stage I non-small cell lung cancer (NSCLC). However, most of these patients are comparatively high-aged and not similar to the patients cohort generally operated with surgery. So, the purpose of this study was to collect results of SBRT for operable and young (70 years old or younger) patients with stage I NSCLC from multiple Japanese institutions.

      Methods:
      We organized a multi-institutional SBRT study group in Japanese Radiological Society (JRS-SBRTSG) and conducted a study for SBRT for stage I non-small cell lung cancer (NSCLC). This is a retrospective analysis to review 252 patients (male 168, female 84) who were medically operable and 70 years old or younger (range,40-74; median, 67 years) with stage I (IA 211, IB 41) NSCLC treated with curative intent by SBRT in 20 institutions of JRS-SBRTSG. Histology was proven in 177 patients (adenocarcinoma 121, squamous cell carcinoma 41, others 15), and the others were diagnosed clinically. Median tumor size was 22mm (range, 5-49mm). A total dose of 40 -70 Gy mainly was prescribed in 4-10fractions. Median calculated biological effective dose (BED) was 107 Gy (range, 75-134 Gy) based on alpha/beta = 10Gy).

      Results:
      The median follow-up period for all patients was 37 months. Overall survival rate (OS) at three and five year was 83.3% and 76.6%, respectively. Radiation pneumonitis of grade 3 or more was noted in 0.8% of the total patients. In the total patients, local control rate (LC) at three year was 89.5%, and LC was significantly better in the subgroup of adenocarcinoma than that of squamous cell carcinoma. According to univariate analysis, female, adenocarcinoma, no emphysema, and no pulmonary interstitial change were better prognostic factors for OS. According to multivariate analysis, pulmonary interstitial change was only a worse survival factor for OS. OS at three and five year in the subgroup of patients without pulmonary interstitial change was 89.7% and 84.0%, respectively.

      Conclusion:
      The outcomes of SBRT for the medically operable and young (75 years or younger) patients with stage I NSCLC in the Japanese large database of practice level was excellent and the overall survival rate would be comparable to that of surgery. The results will support a rationale of applying SBRT for younger and operable patients with operable stage I NSCLC.

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    P2.05 - Poster Session with Presenters Present (ID 463)

    • Event: WCLC 2016
    • Type: Poster Presenters Present
    • Track: Radiotherapy
    • Presentations: 1
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      P2.05-038 - Initial Clinical Experience of VMAT-SBRT with Flattening-Filter-Free Techniques in the University of Tokyo Hospital (ID 4524)

      14:30 - 14:30  |  Author(s): H. Yamashita

      • Abstract

      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 pinnacle[3] treatment planning system with inhomogeneity correction. We targeted at 48 cases with 1) one or two targets; 2) tumor diameter<40mm; 3) dose prescription= 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), 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: central=19:5) were treated with conventional FF VMAT, and remaining 24 patients (peripheral: central=18:6) with FFF VMAT. There were T1 primary lung tumors in 29 patients (FF:FFF= 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: FFF=3.65:1.45(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:FFF= 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: FFF=1:2), Grade2 radiation pneumonitis occurred in 5 cases (FF: FFF=3:2), 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.