Abstract Book

S704

ESTRO 37

Material and Methods Patients with low-moderate risk disease, post- menopausal status, no positive nodes nor close resection margins were enrolled in MARA-3 trial and treated with HMRT plans that were inversely optimized by combining two open fields with six-eight subfields in two tangential beams. Open fields were setup to include the whole breast with a 2 cm flash region and to carry the 80% of beams weight. Primary endpoints were TAC, TTC and TTSC scored by RTOG-EORTC scale. Secondary endpoints were local control and overall survival. All patients received 40 Gy (2.5 Gy/fraction) to the whole breast and an additional simultaneous 4 Gy (2.75 Gy/fraction) to the tumour bed over 16 fractions Results 163 patients (median age: 65, range: 52-84; pT1N0: 81.6%, pT2N0: 18.4%) were enrolled and analyzed. 23% of patients underwent previous chemotherapy. The TAC rate was as follows: G1: 37.4%, G2: 12.3%, G3: 0.6%. Mild hematological (leucopoenia) or lung toxicity were registered in 3.7% of patients. Twenty four-months grade 1 TTC and TTSC free survival were 52.7% and 67.3%, respectively, with no higher grade TTC and TTSC observed. Four patients (2.4%) had radiological findings of lung toxicity. With a median follow-up of 17-months (range: 4-116), no patient showed local or nodal An hybrid IMRT class solution produced negligible severe TAC as well as TTC and TTSC with an excellent local- regional control in patients with low-moderate risk invasive breast cancer EP-1281 MARA 4 trial: a whole breast irradiation with SIB using an hybrid IMRT class solution G. Macchia 1 , S. Cilla 2 , A. Ianiro 2 , M. Boccardi 1 , S. Cammelli 3 , D. Smaniotto 4 , E. Cucci 5 , A.L. Angelini 6 , R. Frakulli 3 , A. Zamagni 3 , V. Dionisi 3 , V. Panni 3 , I. Ammendolia 3 , G. Tolento 3 , G.P. Frezza 7 , A.G. Morganti 3 , F. Deodato 1 1 Radiotherapy Unit, Fondazione di Ricerca e Cura "Giovanni Paolo II", Campobasso, Italy 2 Medical Physics Unit, Fondazione di Ricerca e Cura “Giovanni Paolo II”, Campobasso, Italy 3 Radiation Oncology Center, Department of Experimental- Diagnostic and Specialty Medicine - DIMES- University of Bologna, Bologna, Italy 4 Department of Radiotherapy, Policlinico Universitario “A. Gemelli”- Università Cattolica del Sacro Cuore, Rome, Italy 5 Radiology Unit, Fondazione di Ricerca e Cura “Giovanni Paolo II”, Campobasso, Italy 6 Medical Physic Unit, Department of Experimental- Diagnostic and Specialty Medicine – DIMES- University of Bologna, Bologna, Italy 7 Radiation Oncology Unit, Bellaria Hospital, Bologna, Italy Purpose or Objective To evaluate the results in terms of acute (TAC) and late cutaneous (TTC) and subcutaneous (TTSC) toxicity of a clinical study (MARA-4) on whole breast irradiation with simultaneous integrated boost using an hybrid IMRT class solution Material and Methods Pre- or peri-menopausal patients with negative lymph nodes and with or without close resection margins were enrolled in MARA-4 trial and treated with HMRT plans that were inversely optimized by combining two open fields with six-eights subfields in two tangential beam. Open fields were setup to include the whole breast with a 2 cm flash region and to carry the 80% of beams weight. Primary endpoints were TAC, TTC and TTSC scored by RTOG-EORTC scale. Secondary endpoints were local control and overall survival. All patients received 50 Gy recurrence Conclusion

whole breast radiotherapy (HRT) over standard radiotherapy (SRT) in early breast node negative cancer patients (pts) by a retrospective control group study Material and Methods From January 2004 hypofractionated adjuvant whole breast radiotherapy 42.5 Gy /16 fractions (fr) has been applied in early breast node negative cancer pts following conserving surgery according these criteria : T < 3 cm , age >60 years and favourable dosimetry. From 2004 to 2010 were selected for the hypofractionation regimen 215 pts (HRT arm). The excluded pts were treated with SRT; of these, the first consecutive 215 pts similar by age, tumor factors and accrual time to the HRT pts arm were analyzed in the SRT arm.The local relapse free survival (LRFS) in both arms was obtained and compared on the basis of these parameters ; tumor grade (Nottingham Grading Sistem), receptors status ( ER and PR) , Her2 expression and Ki67 (cut off 20%). Molecular subtypes Luminal A, Luminal B (B+ and B-), Her2 nonLuminal, Triple negative were identified. Statistical analysis with log rank-test and Kaplan–Meier method were carried out. Results At 8 years of mean follow up (7-13 yrs) local relapse was 4.7 % (10/215) in the HRT group and 5.6 % (12/215) in the SRT group. LRFS was 95.3 % in the HRT arm and 94.4 % in the SRT arm but the difference was not statistically significant (p= 0.083). Tumor grade 1-2 was not significant in both groups ( p = 0.86 ) but grade 3 was slight significant (p= 0.0219) for relapse in the SRT group. No differences were found in the Ki 67 cut offs ( p= 0.634 for value < 20% and p= 0.0926 for value >20%). Receptors status did not affect local control significantly (p= 0.0035). Regarding the molecular subtypes no differences were found in all the groups ( LA p= 0.211; LB+ p= 0.111; LB- p= 0.576; TN p= 0.340 ; Her2 non luminal p=0.133). Conclusion In this control group retrospective study tumor grade and molecular factors have shown no impact on local control in the HRT and SRT arms suggesting that early breast node negative tumors may be safely treated with hypofractionated radiotherapy regardless of tumor grade and molecular subtypes. A case control study is in progress. EP-1280 MARA-3 trial: a whole breast irradiation with simultaneous integrated boost in low risk patients M. Boccardi 1 , G. Macchia 1 , S. Cilla 2 , A. Ianiro 2 , P. Viola 2 , C.M. Donati 3 , V. Panni 3 , A. Zamagni 3 , M. Ferioli 3 , I. Ammendolia 3 , G. Tolento 3 , D. Smaniotto 4 , M. Missere 5 , E. Alexopoulou 6 , S. Cammelli 3 , G.P. Frezza 7 , V. Valentini 4 , A.G. Morganti 3 , F. Deodato 1 1 Radiotherapy Unit, Fondazione di Ricerca e Cura “Giovanni Paolo II”, Campobasso, Italy 2 Medical Physics Unit, Fondazione di Ricerca e Cura “Giovanni Paolo II”, Campobasso, Italy 3 Radiation Oncology Center, Department of Experimental- Diagnostic and Specialty Medicine - DIMES- University of Bologna, Bologna, Italy 4 Department of Radiotherapy, Policlinico Universitario “A. Gemelli”- Università Cattolica del Sacro Cuore, Rome, Italy 5 Radiology Unit, Fondazione di Ricerca e Cura “Giovanni Paolo II”, Campobasso, Italy 6 Department of Radiation Oncology, University of Patras Medical School, Patras, Greece 7 Radiation Oncology Unit, Bellaria Hospital, Bologna, Italy Purpose or Objective To evaluate the results in terms of acute (TAC) and late cutaneous (TTC) and subcutaneous (TTSC) toxicity of a clinical study (MARA-3) on whole breast irradiation with simultaneous integrated boost using an hybrid IMRT class solution