ESTRO 36 Abstract Book

S623 ESTRO 36 _______________________________________________________________________________________________

was observed between age subgroups, comparing younger subgroup to the others (p=0.40 and p=0.60). The 2 and 5 year DFS of patients treated with mastectomy was 90% and 81.7% without significant difference between age subgroups (p=0.51). The 2 year DFS in patients treated with adjuvant RT was 91% and 89% in patients treated with mastectomy alone. The 5 year DFS in patients treated with adjuvant RT was 86% and 65% in patients treated with mastectomy alone. No significant difference was detected (p=0.26). The 5 year OS was 70% in patients aged 70-79 years; 55% in patients aged 80-89 years and 14% in patients older than 90 years, with a significant difference (p<0.001). The 5 year OS was 64% and 52% in patients treated with or without adjuvant RT respectively, without significant difference (p=0.12). Conclusion An higher percentage of patients aged between 70-79 years received RT after conservative surgery if compared with the older subgroups. No difference was detected in RT omission after mastectomy. EP-1145 Troponin I for the detection of cardiac toxicity in adjuvant breast cancer radiotherapy K. Boudaoud 1 , H. Allioueche 2 , O. Haderbeche 2 , K. Sifi 3 , S. Taleb 4 , C. Kourteli 5 , K. Benmebarek 3 , M. Setta 6 , S. Serradj 6 , T. Filali 7 , A. Djemaa 4 , N. Abadi 3 1 Scientific research laboratory of molecular biology and genetics- Faculty of Medicine- UC3, Radiation oncology, Constantine, Algeria 2 CHUC, Radiation oncology, Constantine, Algeria 3 Scientific research laboratory of molecular biology and genetics- Faculty of Medicine- UC3, Laboratory of biochemistry, Constantine, Algeria 4 Faculty of medicine- UC3, Radiation oncology, Constantine, Algeria 5 University Constantine 1, Radiation oncology, Constantine, Algeria 6 Faculty of Natural and Life Sciences- UC1, Department of animal biology, Constantine, Algeria 7 Scientific research laboratory of molecular biology and genetics- Faculty of Medicine- UC3, Medical oncology, Constantine, Algeria Purpose or Objective Chemotherapy, targeted agents, hormone therapy and radiation therapy improve survival for women with locally advanced breast cancer but increases the risk for heart failure and cardiomyopathy. Radiation induced heart disease generally occurs with a latent period of 5–10 years. Cardiac troponin I (cTnI) is highly sensitive and specific biomarker of cardiac damage. Our aim was to evaluate the early effect of breast cancer radiotherapy on serum high sensitivity troponin I levels. Material and Methods A total of 28 patients with breast cancer who received adjuvant 3D conformal radiation therapy (RT) were included in a prospective, study. High sensitivity cardiac troponin I (µg/ml) was analyzed from serum samples taken before, during and after two or three radiation therapy weeks. According to cTnI value (≤0.009 or >0.009 µg/ml), patients were allocated into two groups; group A (>0.009 µg/ml) and group B (≤0.009 µg/ml) All patients underwent left ventricular ejection fraction (LVEF, Echo) examination before and after radiation therapy. Dose- volume-histograms (DVH) for the heart were also calculated. Results In the whole study population, cTnI was detectable (>0.009 µg/ml) in 6 (21.42 %) patients before RT, in 5 (17.85 %) during RT and in 6 (21.42 %) patients after RT. Patients with increased cTnI values (group A, N = 6) had higher radiation doses for the heart (5.14 vs, 4.06 Gy). This increase in the cTnI level was more marked in patients

with high blood pressure (33% vs, 4.54%), left-sided breast cancer (66.66% vs, 50%), and those who had received lymph nodes RT; (internal mammary chain (50 vs, 27.27%), supra clavicular and infraclavicular lymph nodes (83.33 vs, 22.72%). Conclusion In spite of the limited patient number, our study shows that circulating cTnI confirms subclinical myocardial damage during and after breast cancer radiation therapy. The role of cTnI as biomarker in predicting future cardiovascular events in patients undergoing adjuvant radiation therapy remains to be determined in large studies and could become a useful research tool. EP-1146 Acute toxicity of hypofractionation with SIB in the radiation therapy for breast cancer J. Fernandez-Ibiza 1 , J. Calvo 1 , O. Coronil 1 , S. San José 1 , E. Puertas 1 , R. Robaina 1 , J. Casals 1 1 Hospital Quiron Barcelona, Radiation Oncology, Barcelona, Spain Purpose or Objective The aim of our study is to evaluate the tolerance and acute/immediate toxicity of a ‘mild’ hypofractionation with simultaneous integrated boost in the radiation therapy after breast conserving surgery in women with diagnosis of early breast cancer. Material and Methods Between January 2015 to October 2016, 100 women with breast cancer diagnosis (Tis-T2, N0-1) were treated with a hypofractionated simultaneous integrated boost (SIB) after breast-conserving surgery, using IMRT, field-in-field technique (FIF) or a mixed technique. Dose prescribed was 45,57 Gy (2, 17 Gy/fr.) in 21 fractions to the breast (+ supraclavicular fossa in 25p), and a simultaneous integrated boost to the surgical bed to achieve 55, 86 Gy (2, 66 Gy/fr.). All patients were treated with chemotherapy (27, 9% were neoadjuvant), except 6 cases of intraductal carcinoma. We registered the acute toxicity at the end of the treatment, one week after and 6 weeks after, prospectively, using the NCI-CTCAE v4.0 scale. Results The acute toxicity at the end of the treatment was grade 1 in 62% of patients, grade 2 in 38% of patients, and grade 3 in 1 patient. One week after the treatment, we observed grade 0 in 2 patients, grade 1 in 54 patients , and grade 2 in 44%. Hence, we detected an increase of gradation toxicity, only in 10 patients (10%), when the toxicity was registered a week later. Finally, 6 weeks after the radiation therapy; 67 % of the patients had recovered their skin’s normal appearance, and 33 % of them persisted with faint erythema (G1) or pigmentation. We collect other parameters of acute toxicity as desquamation, observing no desquamation in 51 % of the patients, dry desquamation in 43% and moist desquamation in 6%. Conclusion This scheme of ‘mild’ hypofractionation with SIB, in the postoperative radiation treatment of early breast cancer after conserving-surgery, showed to be well tolerated and feasible, and is associated with acceptable immediate/acute skin toxicity. Longer follow up is needed to demonstrate acceptable subacute and late toxicity. EP-1147 Radiation induced oesophagitis in breast cancer patients K. West 1 , N. Coburn 1 , R. Beldham-Collins 1,2 , K. Tiver 1 , K. Stuart 2 , V. Gebski 2 1 Nepean Cancer Care Centre, Nepean Hospital, Penrith, Australia 2 Crown Princess Mary Cancer Centre, Westmead Hospital, Westmead, Australia