ESTRO 36 Abstract Book

S348 ESTRO 36 _______________________________________________________________________________________________

According to consensus in literature PMRT was limited to the chest wall (CW-PMRT) in stage pT3 N1 or extended to the lymphatic drainages of apex axilla and supraclavicular nodes (CWLD-PMRT) in stage pT4 N2-3. Patients underwent salvage mastectomy after a previous conservative surgery and RT or with of systemic disease at diagnosis were excluded from the study. Radiotherapy treatment was performed with linear accelerator and 3DCRT technique using X photons of 6 and/or 15 MV energy. Two tangential beam technique was used for CW-PMRT whereas an half beam technique with the addiction of 1-2 anterior-posterior (AP-PA) beam was used for CWLD-PMRT. The prescribed dose was 50 Gy delivered in 25 fractions adding a boost of 20 Gy and 14- 16 Gy for positive and close (<2mm) surgical margins, respectively. Neoadjuvant chemotherapy (CT), adjuvant CT, Trastuzumab, Tamoxifen and systemic endocrine therapy were prescribed according to international guidelines. Radiotherapy was deferred after the completion of adjuvant CT. Univariate and multivariate analyses were performed using SPSS 22 (SPSS Inc., Chicago, IL, USA) technology. Results Between January 2004 and June 2013 a total of 912 patients underwent to total mastectomy; of whom 269 (29,5%) underwent to PMRT and 643 (70,5%) not. Among PMRT group 77 underwent to CW and 202 to CWLD irradiation. The median follow up was 40 months (range, 3-118). No significant difference in terms of LRR was found between the no-PMRT and PMRT group (p=0,175; HR=1,613; CI95%=0,808-3,219). The uni and multivariate analysis of LRR for patients not undergone to PMRT showed a significant correlation with the presence of ECE (p=0,049), Mib-1 >30% (p=0,048) and triple negative status (p=0,001). On the contrary, the triple negative status resulted as the only variable significantly correlated to LRR (p<0,0001) in the PMRT group whereas ECE and Mib-1>30% lost the significance. Finally, no significant difference was shown between CWLD and CW-PMRT (p=0,078; HR=0,375; CI95%= 0,126-1,116). Conclusion Based on our data, we strongly confirm the positive impact of PMRT in local advance disease and recommend to carefully consider it in presence of ECE and Mib-1>30% regardless T and N stage. CW irradiation might be a valid option in selected intermediate disease (i.e. less than 3 positive lymph nodes). Future “well designed” prospective studies are needed to properly validate our results. PO-0666 30 Gy single-dose SBRT to lung lesions: outcome in a large series of patients L. Nicosia 1 , C. Reverberi 1 , L. Agolli 1 , M. Valeriani 1 , V. De Sanctis 1 , C. De Dominicis 2 , G. Minniti 1 , E. Cortesi 3 , M. Martelli 4 , M.F. Osti 1 1 Sant’Andrea Hospital- University of Rome "Sapienza", Radiation Oncology, Rome, Italy 2 Sant’Andrea Hospital- University of Rome “Sapienza”, Department of Radiology, Rome, Italy 3 Policlinico Umberto I- University of Rome “Sapienza”, Department of Radiology- Oncology and Human Pathology, Rome, Italy 4 Carlo Forlanini Hospital- Rome- Italy, Thoracic Surgery Unit, Rome, Italy Purpose or Objective We conducted a prospective study to evaluate the effectiveness, safety and toxicity of a Stereotactic Body Poster: Clinical track: Lung

PO-0665 The role of post-mastectomy radiotherapy (PMRT) and prognostic factors of locoregional recurrence D. Delishaj 1 , S. Ursino 1 , V. Mazzotti 1 , L.R. Fatigante 1 , S. Spagnesi 1 , B. Manfredi 1 , A. Cristaudo- 1 , F. Pasqualetti 1 , A. Sainato 1 , C. Laliscia 1 , M. Pnichi 1 , F. Orlandi 1 , F. Matteucci 1 , R. Morganti 2 , E. Lombardo 1 , M. Cantarella 1 , D. Baldaccini 1 , A. Gonnelli 1 , M.G. Fabrini 1 , A. Molinari 1 , M. Roncella 3 , A. Falcone 4 , D. Caramella 5 , F. Paiar 1 1 Azienda Ospedaliero Universitaria Pisana, Radiotherapy, Pisa, Italy 2 Azienda Ospedaliero Universitaria Pisana, Section of Statistics, Pisa, Italy 3 Azienda Ospedaliero Universitaria Pisana, Breast Surgery, Pisa, Italy 4 Azienda Ospedaliero Universitaria Pisana, Oncology, Pisa, Italy 5 Azienda Ospedaliero Universitaria Pisana, Radiology, Pisa, Italy Purpose or Objective The purpose of the study was to evaluate the outcome of patients (pts) undergone to mastectomy followed or not by post-mastectomy radiotherapy (PMRT) and to investigate the clinicopathological prognostic factors of locoregional recurrence (LRR). Material and Methods We retrospectively reviewed data of patients underwent total mastectomy and sentinel lymph node examination +/- axillary dissection. Patients were staged according to AJCCU/UICC 7° Edition.