ESTRO 36 Abstract Book

S623 ESTRO 36 2017 _______________________________________________________________________________________________

Chuo, Japan 5 National Cancer Center Hospital, Radiation Oncology, Chuo, Japan 6 Kindai University Faculty of Medicine, Radiation Oncology, Osakasayama, Japan 7 Osaka Medical Center for Cancer and Cardiovascular Diseases, Radiation Oncology, Osaka, Japan 8 Saitama Cancer Center, Radiation Oncology, Kitaadachi, Japan 9 Hiroshima University Graduate School of Biomedical Science, Radiation Oncology, Hiroshima, Japan 10 Niigata Cancer Center Hospital, Radiation Oncology, Niigata, Japan 11 National Cancer Center Hospital East, Radiation Oncology and Particle Therapy, Kashiwa, Japan 12 Shizuoka Cancer Center, Radiation and Proton Therapy Center, Sunto, Japan 13 Graduate School of Medicine- Chiba University, Diagnostic Radiology and Radiation Oncology, Chiba, Japan 14 Hyogo Cancer Center, Radiation Oncology, Akashi, Japan 15 Shikoku Cancer Center Hospital, Radiotherapy, Matsuyama, Japan 16 Aichi Cancer Center Hospital, Radiation Oncology, Nagoya, Japan 17 The University of Tokyo Hospital, Radiology, Bunkyo, Japan 18 Tochigi Cancer Center, Radiotherapy, Utsunomiya, Japan 19 Osaka University Graduate School of Medicine, Radiation Oncology, Suita, Japan 20 Graduate School of Medicine- Kyoto University, Radiation Oncology and Image-applied Therapy, Kyoto, Japan 21 Tokyo Metropolitan Cancer and Infectious diseases Center- Komagome Hospital, Radiology, Bunkyo, Japan 22 Tokyo Women’s Medical University, Radiation Oncology, Shinjuku, Japan 23 University of Tsukuba, Radiation Oncology, Tsukiba, Japan Purpose or Objective To evaluate the safety and efficacy of short-course hypofractionated whole-breast irradiation (HWBI) on Japanese women after breast-conserving surgery (BCS), a prospective single-arm confirmatory trial (JCOG0906, UMIN000003200) has been conducted in 25 hospitals. Material and Methods Japanese women who had invasive breast cancer with clinical tumor size of 3 cm or less, no or one to three pathologically positive lymph nodes and pathologically negative inked margin were prospectively registered after BCS with or without adjuvant chemotherapy. The HWBI of 42.56Gy/16fr was delivered to the whole-breast without regional nodal irradiation, and a boost irradiation (BI) of 10.64Gy/4fr to the original tumor bed was added when the surgical margin was 5 mm or less. The recommended treatment period was within 29 days for HWBI and 33 days for HWBI and BI. The primary endpoint was the proportion of pre-specified eight items of grade 2 or higher late adverse reactions (ARs) including telangiectasia, ulceration, fibrosis-deep connective tissue, fracture, pneumonitis, cardiac ischemia/infarction, pericardial effusion and pain-breast occurring between 91 days and three years from the start of HWBI. The sample size was set as 310 patients with one-side alpha of 5%, power of 90%, threshold value of 8%, and expected value of 4%, estimated from the proportion of the late ARs on the historical control including 703 patients followed up for three years or more after conventional fractionated whole-breast irradiation (CWBI) in our pilot survey prior to the present trial. Secondary endpoints included the proportion of treatment completion within the recommended period, early adverse events (AEs)

Conclusion Patients older than 80 treated by Stage I-III breast cancer have long survival after treatment. OS and BCSS is high at five years. Patients with locally advanced preoperatory disease, pathologic tumor size and locorregional irradiation contributed negatively to survival. EP-1156 A clinical trial on hypofractionated whole- breast irradiation after breast-conserving surgery M. Nozaki 1 , Y. Kagami 2 , T. Shibata 3 , K. Nakamura 4 , Y. Ito 5 , Y. Nishimura 6 , Y. Kawaguchi 7 , Y. Saito 8 , Y. Nagata 9 , Y. Matsumoto 10 , T. Akimoto 11 , T. Nishimura 12 , T. Uno 13 , K. Tsujino 14 , M. Kataoka 15 , T. Kodaira 16 , K. Shiraishi 17 , K. Inoue 18 , F. Isohashi 19 , M. Hiraoka 20 , K. Karasawa 21 , S. Izumi 22 , H. Sakurai 23 1 Dokkyo Medical University Koshigaya Hospital, Radiology, Koshigaya, Japan 2 Showa University School of Medicine, Radiation Oncology, Shinagawa, Japan 3 National Cancer Center, Statistical Section- The Japan Clinical Oncology Group Data Center, Chuo, Japan 4 National Cancer Center, Study Coordination Section,