ESTRO 36 Abstract Book

S618 ESTRO 36 2017 _______________________________________________________________________________________________

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 Purpose or Objective To investigate if a relationship exists between the dose volume parameters leading to moderate oesophagitis in early breast cancer patients receiving radiotherapy to both the breast and supraclavicular nodes (SCF). Oesophagitis has been widely reported in treatment sites such as lung and head and neck, however there is limited data for breast cancer patients. Material and Methods Seventy-seven breast cancer patients receiving radiotherapy to their breast and SCF were recruited for the study. Patients were prescribed 50Gy to the breast or chest wall and SCF +/- a simultaneous integrated boost to the tumour bed of 57Gy. Analysis of the dose volume histogram (DVH) data of the irradiated volume of the oesophagus was performed. Patients were graded twice weekly with a modified RTOG oesophagitis scale to determine the onset, duration and severity of reported oesophagitis. Patients who experienced a grade 1B or worse by the end of their treatment were followed up twice weekly until the symptoms of oesophagitis had resolved. Results From the 77 patients analysed, 2 patients had no reaction, 22 patients reached a grade 1A reaction, 30 patients reached grade 1B, 16 patients reached grade 2A and 7 patients reached grade 2B. The onset of each grade reached throughout the treatment showed those who reached a maximum grade of 1B, did so at an average of 13 fractions. Patients that reached a maximum grade of 2A, reached grade 1B at 10 fractions and 2A at 18 fractions. Patients that reached a maximum grade of 2B reached the 1B grade at just 8.3 fractions, the 2A at 14 fractions and the 2B at 21.7 fractions suggesting the faster the onset, the worse the outcome for the patient. The average mean dose to the oesophagus for patients that had a maximum grade of 0-1A was 31.95Gy, 1B was 32.46Gy, 2A was 34.22Gy and 2B was 34.64Gy. The average maximum doses recorded for 0-1A was 49.86Gy, 1B 50.44Gy, 2A 50.36Gy and 2B 51.26Gy; maximum doses did not seem to have an impact on the incidence of oesophagitis, however the mean dose showed a steady increase from grade 0-1A up to 2B. Also recorded was the mean dose delivered at each grade, based on when the patient reported the changes.