ESTRO 37 Abstract book

ESTRO 37

S614

6 Azienda Ospedaliero Universitaria Pisana, Section of Statistic, Pisa, Italy

Alled 1 , B. García Gímeno 1 , M. Matute Najarro 2 , C. Casamayor Franco 2 , C. García Mur 3 , S. Cruz Ciria 3 , E. Hernando Almudi 2 , P. Rubio Conde 4 , I. Vicente Gómez 4 , C. Scuin 1 , C. García Aguilera 1 , M. Tejedor Gutierrez 1 1 Hospital Universitario Miguel Servet, Servicio de Oncología Radioterápica, Zaragoza, Spain 2 Hospital Universitario Miguel Servet, Servicio de Cirugía General, Zaragoza, Spain 3 Hospital Universitario Miguel Servet, Servicio de Radiodiagnóstico, Zaragoza, Spain 4 Hospital Universitario Miguel Servet, Servicio de Ginecología, Zaragoza, Spain Purpose or Objective The patients with early breast cancer can be treated with conservative surgery and intraoperative radiotherapy, considering that, according to published studies, it has demonstrated non inferiority in terms of effectiveness and toxicity compared with external beam radiotherapy. The main purpose of this study is to evaluate the toxicity and cosmetic results secondary to this technique. Material and Methods In the period between may 2015 and september 2017 we have selected postmenopausal breast cancer patients, with invasive ductal carcinoma, luminal A and B, tumour size ≤ 20 mm, without lymphatic affectation and in which conservative surgery was performed (according to the Gec ESTRO and ASTRO criteria). During the surgical intervention, through a low energy (50Kv) X ray device, 20 Gy were administered directly over the tumour bed, with a distance between the applicator and the skin ≥ 1 cm. Clinical and sonographic control was performed at the 1 st and 3 rd month and mammographic control at 6 th and 12 th month after treatment. The toxicity outcomes were evaluated according to the Common Terminology Criteria for Adverse Events (CTCAE) Version 4.0. Results 242 patients were selected with a median age of 66 years old , which received intraoperative radiation therapy (IORT) as an exclusive treatment option. After the definitive pathological results it was necessary to administer external beam radiation over the breast in 26% of cases , taking in these cases IORT as a boost. The median follow-up was 16 months ( 0,1- 29 months). After the 1 st month of treatment, 73% of the patients presented seroma on the tumour bed that decreased at the 3 rd month after treatment.The majority of the patients did not have any symptom due to the radiation therapy, being reported acute radiodermititis grade 1 in a 23% and grade 2 in an 3%. and grade 3 in 1% of the cases. As late toxicity, radiodermititis grade 1 was observed in 7 % of the patients, telangiectasia grade 1 in 1,6 % and glandular fibrosis grade 2 in a 3% after a year of the ending of the treatment. Conclusion The intraoperative radiation of the breast reduces the time of treatment from 3-5 weeks to one only application during the surgery, with a feasible acute and late toxicity and good cosmetic outcomes. In patients with associated comorbidities or with a large displacement to the medical centre, this technique can be considered as a treatment option. PO-1090 Effect of radiotherapy on bonding and bonding interface to substrate of permanent teeth. A.M.D. Queiroz 1 , H. Francisco de Oliveira 2 , P. Nelson filho 1 , J. Arid 1 , R. Guenca paula dibb 3 , L. Assed bezerra da Silva 1 , R. Assed segato 1 1 University of São Paulo, Clínica Infantil, Ribeirão Preto,

Purpose or Objective A prospective instrumental assessment of late dysphagia using SWOARs-sparing IMRT for nasopharynx and

oropharynx cancers. Material and Methods

Eligibility criteria were pts affected by nasopharynx and oropharynx cancers (Stage II-IVA) candidates for curative RT treatment with bilateral neck irradiation. Pts underwent induction CT and/or HN oncologic treatment (surgery or RT) as well as diagnosis of concomitant comorbidity which might compromise deglutition function were excluded. Pts experienced recurrence or metastatic disease within the time of the study were dropped out from the study. Eight swallowing related structures (SWOARs) were outlined according to Christianen et al. guidelines and included in the IMRT plan objective function: superior, middle and inferior constrictor muscles (SPCM, MPCM and IPCM), supraglottic (SL), glottis larynx (GL), cricopharyngeal muscle (CPM) and cervical esophagus (EC) as well as the major salivary glands, oral cavity and pharyngeal mucosa which were outside the targets. In the IMRT optimization cost function, target coverage replaced sparing of any part of the SWOARs and other secondary organs at risk except the spinal cord and brainstem. Objective instrumental assessment included Fiberoptic Endoscopic Evaluation of Swallowing (FEES) and Videofluoroscopy (VFS) at baseline, at 6 and 12 months after treatment. FEES assessed the pharyngeal residue according to the Farneti pooling score (P-score) as follows: 4-5 no dysphagia; 6-7 mild dysphagia; 8-9 moderate dysphagia; 10-11 severe dysphagia. 3 different consistencies were tested for the P-score: liquid (L), semisolid (SS) and solid (S). VFS assessed penetration- aspiration according to the Penetration Aspiration Scale (PAS) and 2 different consistencies of the bolus were tested: thin liquid barium (L) and paste barium (S). Results Overall 38 pts were evaluable for this study. Median and range doses received by the SWOARs were: 59 Gy for the SPCM, 55 Gy for the MPCM, 41Gy for the IPCM, 40Gy for the CPM, 52Gy for the BOT, 40Gy for the SL, 40Gy for the GL and 25Gy for the EC. Only 2 pts required hospitalization and enteral nutrition. Among the 38 evaluable pts 7 (18%) experienced a locoregional recurrence (6 local and 1 local and regional) of whom 5 underwent a subsequent metastatic progression. Two pts had distant metastases progression without locoregional recurrence. Overall, after a median follow-up of 33 months (range 12-56), 3 pts (7,7%) died due to cancer and 1 pt died of cardiovascular disease. There was a significant worsening of the P-score at 6 months both for SS (p=0,015) and S (p<0,001) which persisted only for S at 12 months (p<0,0001). Similarly there was a significant worsening of the PAS score at 6 and 12 months (p=0,065 and 0,039, respectively) for S bolus. An overall 3-7% and 10-14% of aspiration after L and S was observed, respectively. Conclusion Promising results using a SWOARs-sparing IMRT technique are reported. So, treatment plans should be optimized for reducing doses to these structures. PO-1089 IORT for breast cancer treated with Axxent Xoft. Our experience: toxicity analysis J.G. Molina Osorio 1 , R. Ibáñez Carreras 1 , J.R. Oliver Guillén 2 , M. Lanzuela Valero 1 , A. Miranda Burgos 1 , L.