ESTRO 37 Abstract book

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ESTRO 37

failure was defined as a replacement or loss of the implant or conversion to flap. Results Seventy-two and 76 pts underwent IBR with TE and PI, respectively. RF was evaluated in all the pts with PI except 1 who removed her implant during PMRT and in 63 TE-pts since 9 pts never replaced the TE with a PI. Median follow-up from surgery was 107 months. The two groups were comparable for most of the characteristics analyzed. RF occurred in 22/63 (34.9%) TE-pts and 40/75 (53.3%). A statistically significant difference between median interval time to RF was observed with an earlier onset in the TE-pts compared to PI-pts (109.2 vs 157.7 months, p=0.029). The implant weight was the only characteristic maintaining a significant impact on RF at univariate and multivariate analysis. Conclusion In the long run, PMRT after IBR provides an acceptable risk of RF, with an earlier onset for the TE-pts. However, we believe that the choice between PI and TE must be tailored on the individual patient irrespective of potential PMRT. EP-1345 Prevalence of asymptomatic pericardial effusion in breast cancer patients referred for RT M. Arquez-Pianetta 1 , L. Torres 1 , C. Ligero 2 , M. Sousa 3 , M. Arenas 1 , M. Bonet 1 1 Hospital Universitari Sant Joan de Reus, Radiation Oncology, Reus, Spain 2 Hospital Universitari Sant Joan de Reus, Cardiology, Reus, Spain 3 Hospital Universitari Sant Joan de Reus, Radiology, Reus, Spain Acute pericarditis is one of the conditions classically attributed to radiotherapy (RT) in tumours requiring thoracic irradiation. The impact or contribution of previous treatments like chemotherapy (CHT) has not been studied in detail. A high proportion of patients with pericardial effusion (PE) are asymptomatic and the detection of a chronic PE might be an incidental finding. While echography is the gold standard technique to its diagnosis, is not unusual to detect signs of PE in the siumlation CT of breast cancer patients being referred for RT. Objectives To determine the prevalence of radiological signs of PE in a cohort of breast cancer patients previously treated with surgery, with ot wihtout CHT, referred for adjuvant RT. Material and Methods CT images of 151 patients (88 in the CHT group and 63 in the non-CHT group) were reviewed from 2014 to 2015. The presence and volume of radiological signs of PE, assesed by two radiation oncologists and an experimented radiologist, were recorded. The presence of cardiovascular risk factors and intercurrent infective diseases previously to RT were assessed as well. The prevalence of CT signs of PE was compared between CHT and non CHT patients. Results The prevalence of CT signs of PE for the whole grop was 13.25%. All patients were assymptomatic. In the CHT group, 13/88 cases had these signs with a mean volume of 5.01cc (range: 2,9cc-10cc). In the non-CHT group 7/63 patients had signs of PE, with a mean of 6.81cc (range: 4.5cc – 11.2). There were no statistical differences in prevalence between the groups (p=0.51, chi-square test). Conclusion The prevalence of small volume PE in breast cancer patients referred for RT is not negligible. Chemotherapy does not seem to be a risk factor. A next step of this study is to correlate this findings with the incidence of acute radiation-induced pericarditis in our series and to Purpose or Objective BACKGROUND

Table 1: Deformation image protocol analysis.

Conclusion Velocity© can afford an optimized deformable

registration after lumpectomy helping to get a more accurate definition of the tumor bed before postoperative irradiation in the conservative treatment setting of breast cancer. EP-1344 Long-term reconstruction failure after postmastectomy RT to temporary expander or permanent implant S. Dicuonzo 1 , M. Leonardi 2 , D. Radice 3 , A. Morra 2 , V. Dell'Acqua 2 , M. Gerardi 2 , D. Rojas 4 , A. Surgo 2 , F. Cattani 5 , R. Cambria 5 , C. Fodor 3 , F. De Lorenzi 6 , V. Galimberti 7 , R. Orecchia 8 , B. Jereczek-Fossa 9 1 Dicuonzo Samantha, Division of Radiation Oncology, Milan, Italy 2 European Institute of Oncology, Division of Radiation Oncology, Milan, Italy 3 European Institute of Oncology, Department of Epidemiology and Statistics, Milan, Italy 4 European Institute of Oncology and University of Milan, Division of Radiation Oncology and Department of Oncology and Hemato-onco, Milan, Italy 5 European Institute of Oncology, Unit of Medical Physics, Milan, Italy 6 European Institute of Oncology, Department of Plastic and Reconstructive Surgery, Milan, Italy 7 European Institute of Oncology, Department of Surgery, Milan, Italy 8 European Institute of Oncology and University of Milan, Department of Medical Imaging and Radiation Sciences and Department of Oncology and Hemato-oncology, Milan, Italy 9 European Institute of Oncology and University of Milan, Division of Radiation Oncology and Department of Oncology and Hemato-oncology, Milan, Italy Purpose or Objective Immediate breast reconstruction (IBR) followed by postemastectomy radiotherapy (PMRT) is becoming an integral part of breast cancer treatment, due to younger age of detection and to the trend to offer PMRT to an increasing number of patients (pts) with small tumors or with fewer positive lymph nodes based on the results of large studies showing benefit of PMRT. PMRT is well known for having a negative impact on IBR, but several papers seem to invalidate these data. This study reports the rate of breast RF after PMRT at our Department, comparing tissue expander (TE) with

permanent implant (PI). Material and Methods

Pts that underwent mastectomy and immediate TE/PI reconstruction followed by PMRT between June 1997 and December 2011 were retrospectively evaluated. RF