Abstract book - ESTRO meets Asia

S76 ESTRO meets Asia 2018

P. Sarkar 1 , S. Mitra 1 , J. Koley 1 , S. Dutta 1 , M. Chakraborty 1 , S. Mondal 1 , J. Basak 1 , A. Dinda 1 , P. Dutta 1 1 Narayana Superspeciality Hospital, Radiation Oncology, Kolkata, India 2 Midnapore Medical College, Radiation Oncology, Kolkata, India Purpose or Objective Radiotherapy is an integral part of management in all breast conservation surgeries (BCS) and for a large percentage of postmastectomy patients. Conventionally fractionated radiotherapy (1.8-2 Gy/fraction) lasts for 6 weeks in post-BCS patients and 5 weeks for postmastectomy patients. However, over last two decades few large randomized control trials have confirmed that appropriately dosed hypofractionated radiotherapy is equally safe and effective. Here we present our institutional experience with hypofractionated radiotherapy in breast carcinoma regarding locoregional control, acute normal tissue toxicities and cosmesis. Material and Methods In this prospective, single arm, single institutional, phase II study, between July 2013 to December 2015, 94 early and locally advanced breast carcinoma patients have received hypofractionated radiotherapy (40 Gy/15#/03 weeks followed by 12.5 Gy/05#/01 week as applicable). After completion of radiotherapy patients were followed up every 03 monthly and assessed for locoregional control, toxicities and cosmesis clinically. Results 94 women (46 post BCS and 48 post MRM) received hypofractionated radiotherapy between July 2013 and December 2015. After a median follow up of 31 months 1 patient each developed local and regional recurrence and 2 patients developed distant metastasis. No post-BCS patient developed in-breast recurrence. 3 year DFS was 91.6%. There was no grade 4 acute toxicity and at the time of last follow up 16 patients (17 %) had fair, 28 patients (29.8%) had good and 2 patients (2.1%) had poor cosmesis. Conclusion Hypofractionated radiotherapy is safe and effective across both early and locally advanced breast carcinoma with good cosmetic outcome. PO-189 Deep inspiration breath hold (DIBH) for left breast cancer: a dosimetric comparison M.I.M. Lei 1 , H. Hu 1 , G.L. Xiao 1 1 Kiang Wu Hospital, Oncology, Macau, Macau Purpose or Objective Deep inspiration breath hold (DIBH) technique has been accepted as an effective measure for sparing organs at risk (OAR) for early-staged left breast cancer (LBC). However, little is known about the efficacy on the scenario with regional nodal irradiation (RNI). The aim of this study is to present the dosimetric results of DIBH technique comparing to conventional free breathing (FB) method for LBC patients treated at our centre and investigate the interplay of regional nodal irradiation (RNI) in dosimetric benefits. Material and Methods Forty-one female patients with LBC referred to our centre between April 2016 and December 2017 were retrospectively studied. Each patient underwent breath hold CT (BHCT) and free breathing CT (FBCT). The condition of the breath hold was monitored by the real- time position management (RPM) system. Those who could not hold their breath more than 20 seconds or reproduce stable breath hold were excluded. DIBH and FB plan generated on the respective CT sets were compared. The dosimetric parameters of the OARs, including heart, left- anterior coronary artery (LADA), lungs, left lung and right breast, as well as the homogeneity and conformal index

values (HI and CI) of the target were collected and analysed. The data were then divided into two subgroups (WBRT and B/CWRT+RNI) for further investigation. Wilcoxon signed rank test and Mann-Whitney test (SPSS v.20) were performed. A p -value < 0.05 was considered significant. Results Comparing DIBH to FB plans, no significant differences in CI and HI values ( p= 0.223 and 0.201respectively) were observed indicating that comparable coverage and homogeneity were achieved. The dosimetric parameters of OARs were significantly improved in favour of DIBH compared to FB, with the greatest dose reductions found in the heart Dmean (FB=6.53 vs DIBH=4.92 Gy) and LADA Dmean (FB=27.21 vs DIBH=18.71 Gy) representing a decrease of 24.65% and 31.24% respectively. For those who received whole breast only RT (WBRT, n=19), the heart Dmean was 6.47 Gy in FB compared to 4.78 Gy in DIBH ( p =0.000). While for those assigned for B/CWRT+RNI (n=22), the heart Dmean decreased from 6.53 Gy in FB to 4.92 Gy in DIBH ( p =0.000). Heart Dmean, LADA Dmean and left lung V20 were chosen to compare the organ sparing effect of DIBH in two patient subgroups. No significant differences were found in the degree of reduction in heart Dmean and LADA Dmean ( △ 24.26 vs △ 18.18%, p =0.105; △ 24.74 vs △ 17.77%, p =0.063). However, more prominent reduction in left lung V20 were seen in B/CWRT+RNI compared to WBRT ( △ 16.53 vs △ 24.86%, p =0.026). Conclusion DIBH provides effective OAR sparing outcomes especially for cardiac and pulmonary organs. When investigating the organ sparing effect of DIBH, patients treated with or without RNI received comparable dose reductions in heart Dmean and LADA Dmean. While left lung V20 reduction seems greater in B/CWRT+RNI group with DIBH. PO-190 Salvage Radiotherapy with a new radio-sensitizer (KORTUC) for 2 breast cancer cases S. Obata 1 , Y. Ogihara 1 , T. Takeda 1 , S. Miyagi 1 , Y. Ohta 1 , T. Kan 1 , S. Kanegae 1 , Y. Inoue 1 , A. Kuroiwa 1 , K. Inoue 1 , K. Watanabe 1 , H. Orita 1 , A. Arioka 1 1 Nagasaki Prefecture Shimabara Hospital, Department of Radiology and Radiotherapy, Shimabara, Japan Purpose or Objective When a local lesion recurs after a breast cancer operation and irradiation, it is recommended that you should avoid the re-irradiation to the part, because of accumulating the excessive radiation dose from the aspect of the adverse event. In addition, the significance of the re-irradiation will be doubted for a reason with a few effects of the prior radiation therapy. However, the patient will really fall into miserable situation that we cannot save if other therapeutic methods do not succeed. In such a case, we must add wiping out the treatment resistances, which are in the cancer itself by nature or acquired by the stimulation with prior various treatments. Radiotherapy with a new radio-sensitizer (KORTUC) is regarded as the treatment method that is suitable to such a situation. Hydrogen peroxide, which is a kind of active oxygen, defeats both the existence of the hypoxia environment and the excessive antioxidant enzyme which are causes of the treatment resistances and enforces an effect of the radiation therapy and may reduce the total radiation dose of the salvage treatment. We herein experienced the two cases and report them. Material and Methods Case1: 42-year-old-woman underwent an operation [left Bp+Ax invasive ductal carcinoma, n+, ER+, PgR+, HER2(2+), FISH?] with post operative irradiation 50Gy and administration of UFT and Tamoxifen in 2004. 10 years