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absolute risk of cardiovascular diseases was below 0.1% in the three sitatuations analyzed. (Table 1)

satisfactory distribution; SIB was added in 22 patients (45%). Severe grades of cutaneous toxicity (G3 and G4 RTOG) were no observed; grade 2 acute skin side-effects were significantly low. At the end of the treatment only 4 patients (8%) needed topic steroid therapy for G2 dermatitis, which ameliorated within 3 weeks after irradiation; 17 patients (35%) had G1 erythema; 27 women (56%) had no clinical side effects. Two weeks after RT only 15 patients (31%) showed a residual G1 toxicity, spontaneously and quickly resolved.

Conclusion RT of nodal chains increases the heterogeneity of planning and the doses in organs at risk, especially the lungs. In recommending elective lymph node RT, one must consider its risks and benefits, taking into account the oncology factors and the RT plan of each patient. Special attention must be given to patient who smoke in which RT of drainage will lead to a significant increase in lung MD, as the increased risk of radiation-induced lung cancer may surpass the benefits observed with this treatment. EP-1303 Less is good: once-weekly hypofractionated radiotherapy for early breast cancer in elderly women E. Bonzano 1 , G. Siffredi 1 , M. Guenzi 1 , R. Corvò 1 1 IRCCS Policlinico San Martino and University- Genoa- Italy, Department of Radiation Oncology, Genoa, Italy Purpose or Objective The aim of our study was to evaluate one weekly hypofractionated Adjuvant Radiotherapy (RT) in elderly patients affected by early breast cancer and to report preliminary clinical outcomes, acute skin toxicity and Our study was conducted on 49 patients treated from October 2016 to June 2017. Patients underwent Adjuvant Radiotherapy with a hypo-fractionation regimen: 28,5 Gy / 5 fractions / 1 fraction weekly plus/minus a 2.5 Gy Simultaneous Boost (SIB) on tumour bed in “high risk” cases. Patients were aged over 70 years old (median age 79 y.o., range 72-95), with no severe comorbidities, pT1- 2N0-1a, with different biological subtypes, laterality and size (overall medium). Treatment was delivered in supine position, with tangential fields and constraints of conventional 3D-CRT for lungs and heart; V20=0 for Left Anterior Descending Artery (LADCA) was translated to V12 for radiobiological calculation. Field-in-field technique was used to increasing dose distribution homogeneity. Acute skin toxicity and clinical outcomes were assessed based on RTOG (Radiation Therapy Oncology Group) scales and evaluated before, during each fraction, at the end of RT and at 2, 4 weeks and at 6 months after treatment. Results The median follow-up was 7 months. Clinical o utcome was good, no remarkable changes in breast appearance were detected. Treatment was well tolerated in all cases except a 90 y.o. woman, who interrupted therapy after 3 fractions. Tangential fields were sufficient to achieve treatment feasibility. Material and Methods

Conclusion This hypofractionated schedule has proven to be a feasible treatment, with poor acute skin toxicity. Moreover, it represents a facilitation to radiation treatment for elderly patients, who hardly acceed to the hospital, limiting the number of accesses and improving the safety of this regimen. Its actual effectiveness will be tested in a longer follow-up. EP-1304 Patterns of loco-regional failure in early breast cancer treated by WBRT in lateral position H. XU 1,2 , B. Estelle 1 , C. Emilie 1 , K. Samar 1 , L. Christelle 1 , B. Louis 1 , F.B. Nathalie 1 , B. Anne 1 , F. Alain 1 , K. Youlia M. 1 1 Institut Curie, Radiation Oncology, Paris, France 2 Ruijin Hospital- Shanghai Jiaotong University School of Medicine, Radiation Oncology, Shanghai, China Purpose or Objective To evaluate loco-regional control and describe the patterns of failure in patients (pts) with breast cancer irradiated by previously published whole breast radiotherapy (WBRT) in the isocentric lateral decubitus position (ILD). Material and Methods We studied 832 consecutive female patients with early stage BC treated by breast conservative surgery (BCS) followed by 3D conformal WBRT-ILD between 2005 and 2010. All patients who experienced loco-regional recurrence have been studied. Five-year RFS and OS rate were calculated. Mapping patterns of regional recurrences was also performed. Results Among the 832 women included 51% of the patients presented left side BC and 49% right. The median age was 61.5 years (range, 29-90). Different types of fractionation schemes were used: 66 Gy in 33 fractions (fr) (46.5%), 50Gy/25 fr (17.9%), 40Gy/15 fr or 41.6Gy/13 fr (26.1%) and 30Gy/5 fr (9.5%). With the median follow-up of 6.4 years, only 36 locoregional recurrences were observed without any association with the fractionation regimen (p=0.2). In the population of 36 pts, 28 cases (77.8%) presented with "in breast" local recurrences (LR), 2 cases (5.6%) with LR and regional lymph node recurrence (RLNR), and 6 cases (16.6%) with RLNR alone (in non- irradiated areas). The median latency recurrence time was 50 months. Complete cartography of the recurrences was realized and in the most cases the LR was situated close to the initial tumor bed. The LR cases showed a significantly lower metastasis rate, P<0.001 ， and had a