Abstract Book

S708

ESTRO 37

EP-1288 Concurrent chemoradiaton(CCRT) for locally advanced/inflammatory or recurrent breast carcinoma(LABC) P. Mavroeidi 1 , A. Varveris 1 , A. Spanakis 1 , C. Varveris 1 1 heraklion University Hospital, Radiotherapy-Oncology, Heraklion- Crete, Greece Purpose or Objective To assess the safety & efficacy of CCRT for LABC .Traditionally, neo-adjuvant chemotherapy is being used for pts with inoperable disease in Lung, Esophageal , Rectal cancer. In recent years upfront CCRT has increasingly been used in pts with operable disease. Material and Methods 20 pts treated between 2006-2016 were reviewed. 8 pts (40%) presented with primary disease (locally advanced or inflammatory : T4N0-3M0-1) and 12 pts (60%) had recurrent disease. A total of 9 pts (45%) had evidence of M1 disease including skin metastases. 5 pts (25%) had already received 50 Gy to the breast /chest wall and 16- 20 Gy as a boost. RT consisted of 50.4 Gy as re- irradiation to 70.2 Gy as radical tx in 1.8 Gy /fraction/day, 5 days/wk. Liposomal Doxorubicin (caelyx) was administered at 14 mgr/m 2 /weekly concurrently with RT, according to a previous study of the department. 7 pts(35%) underwent planned mastectomy after CCRT completion. Results The grade of acute and late toxicity was evaluated ,as well as response to treatment, local relapse free survival (RFS) and overall survival (OS).Of the 5 pts with re- irradiation and 15 with LABC acute toxicity included moist desquamation (n=5 , n=12 respectively), dry desquamation (n=3/15) , and grade 3 neutropenia in 4/12 pts (20%) , who had already been treated with different chemotherapy schedules and in 3/8 pts(37.5%) treated with upfront chemotherapy. Late side effects included arm lymphoedema (n=7), decreased level of arm motion (n=5) and skin toxicity , none life- threatening. Overall clinical response (CR) was 100%, with a (complete) cCR observed in 3/20 pts (15%) and a cPR (clinical partial response) in 17/20 pts (85%). Of 20 pts assessable , 7 were treated with surgery , which resulted in 2/7 pCR (pathologic) and 5/7 pPR .At a median follow-up time of 26.2 months the 2-year RFS and OS were 65% (13/20) and 75% (15/20) respectively. Conclusion CCRT with caelyx is effective and well tolerated treatment with an acceptable toxicity profile for pts with LABC. Further investigation of CCRT in LABC patients is needed. EP-1289 ABPI with 3D-CRT and image-guided IMRT – 6 year results of a phase II trial N. Mészáros 1,2 , G. Stelczer 1 , T. Major 1 , E. Mozsa 3 , Z. Zaka 1 , L. Janvary 1 , J. Fodor 1 , C. Polgar 1,2 1 National Institute of Oncology, Radiotherapy, Budapest, Hungary 2 Semmelweis University- Faculty of Medicine, Department of Oncology, Budapest, Hungary 3 Landesklinikum, Department of Radiooncology and Radiotherapy, Wiener Neustadt, Austria Purpose or Objective To present the 6-year clinical results of accelerated partial breast irradiation using three dimension conformal radiation therapy (3D-CRT) and image-guided intensity- modulated radiation therapy (IG-IMRT) following breast- conserving surgery, for early-stage breast cancer. Material and Methods Between 2006 and 2014, 104 low risk breast cancer patients were treated with postoperative APBI given by means of 3D-CRT (n=44) using 3-5 non-coplanar, isocentric wedged fields, or IG-IMRT (n=60) using kV-CBCT guidance for each fraction. The total dose of APBI was

36.9 Gy (9 x 4.1 Gy) using twice-a-day fractionation for 5 consecutive days. Survival results, side effects, and cosmetic results were assessed. Results At a median follow-up of 72 months (range: 48-136) three (2.9%) local recurrences, one regional (<1%) and one contralateral breast recurrences (<1%) were observed. Overall six patients (5.8%) died, among these 2 (1.9%) deaths were breast cancer related. Six (5.8%) secondary tumours were observed. The 6-year local (LRFS), and regional recurrence free (RRFS) survival was 98.5%, and 98.7%. The 6-year disease-free (DFS), cancer specific (CSS) and overall survival (OS) was 95%, 97.6% and, 96%, respectively. Acute side effects included grade 1 (G1) and G2 erythema in 54 (51.9%) and 2 (1.9%), G1 parenchymal induration in 43 (41.3%), G1 and G2 pain in 26 (25%) and 2 (1.9%) patients. No ≥G3 or higher acute side effect occurred. Late side effects included G1 telangiectasia in 16 (15.4%), G1, G2, and G3 fibrosis in 29 (27.9%), 5 (4.8%) and 1 (0.9%) patients, respectively. Asymptomatic (G1) fat necrosis occurred in 9 (8.7%) patients. No G2 or higher late side effects occurred with IMRT. The rate of excellent/good and fair/poor cosmetic results was 97 (93.2%), and 7 (6.8%) respectively. Conclusion : Six-year results of ABPI with 3D-CRT and IG- IMRT are encouraging. Toxicity profile is comparable to other results using multicatheter APBI brachytherapy. EP-1290 Evaluation of incidental internal mammary chain dose coverage with different radiation techniques Y. Song 1 , W. Wang 1 , J. LI 1 , T. Sun 1 , P. QIU 2 , M. Xu 1 , Q. Shao 1 1 Shandong Cancer Hospital Affiliated to Shandong University- Shandong Academy of Medical Sciences- Jinan- Shandong province- China, Radiation Oncology, Jinan, China 2 Shandong Cancer Hospital Affiliated to Shandong University- Shandong Academy of Medical Sciences- Jinan- Shandong province- China, breast surgery, Jinan, China Purpose or Objective The study aimed to evaluate the dosimetric parameters of incidental irradiation to internal mammary chain (IMC) from inverse intensity-modulated radiotherapy (I-IMRT), field-in-field (FIF) intensity-modulated radiotherapy (F- IMRT) and three-dimensional conformal radiotherapy (3D- CRT) and to estimate the factors affecting the magnitude Eighty-four patients with breast-conserving surgery were selected. Seventy patients received tumor boost and sixty-nine percentage of tumor beds were located in the third intercostal space. The breasts, tumor beds and IMC, including the first three intercostal spaces (ICS1-3), were contoured. Three different plans were generated by one physicist using the Eclipse treatment planning system. The prescription doses for the breast and tumor bed were 50.4 Gy/28 F and 60.2 Gy/28 F, respectively. Moreover, 50 Gy/25 F was prescribed for the whole breast if there was no tumor bed boost. The IMC was not included in the planning target volume. Doses to the organs at risk (OARs) were optimized to meet the requirements. Additionally, none of the patients underwent irradiation of the supraclavicular nodes. Results The median D mean values of the three intercostal spaces of the IMC (IMC total ) were 2951.4 cGy, 2973.9 cGy and 2740.2 cGy for 3D-CRT, F-IMRT and I-IMRT, respectively. Differences were not detected between any of the plans. After separating ICS1-3 for further analysis, neither of the mean doses of ICS1-2 was significantly different between the plans. However, for ICS3, the median D mean was highest for I-IMRT (3818.2c Gy), and those for 3D-CRT of IMC receiving dose. Material and Methods