ESTRO 38 Abstract book

S395 ESTRO 38

what the patients with 28.5 Gy. There were no differences in locoregional control between both treatment schedules. Locoregional control was 94.2% at 5 years (figure 2) and progression-free survival was 84.5% at 5 years. At a median follow-up of 46.3 months, 178 patients (74.2%) was alive and disease free and 30 (12,5%) patients die and disease free.

surgical approach (SLB vs axillary lymph node dissection- ALND). In case of disease onset with limited lymph node involvement (cN1), the same therapeutic option is chosen based on the response obtained after NAC but not based on the axillary surgical approach: in case of residual disease after NAC (ypN+), post-mastectomy RT is performed in the 79% and 76% of cases after SLB or ALND, respectively. In this setting, breast RT was administrated in 97% of pts after BCs, with hRT in 49% of cases. Conclusion This survey demonstrated the high interest for breast RT in the majority of Italian Centers. Some practices as rRT and RT omission in particular clinical settings need further verification before entering in current clinical practice. Future national clinical collaborative studies are advocated in order to investigate these controversial topics about BC RT. PO-0767 Long-term results of adjuvant hypofractionated radiotherapy for breast cancer in elderly patients. M.J. Garcia Anaya 1 , I. García Ríos 1 , S. Segado 1 , Á. Fernández Forné 1 , C. Jódar López 1 , J.A. Medina Carmona 1 1 Hospital Universitario Virgen de la Victoria, Radiation Oncology, Malaga, Spain Purpose or Objective Radiotherapy is an important treatment for the local control of breast cancer. More than 30% of breast cancer cases occur in women 70 years of age or older, but adjuvant radiation therapy is often omitted in older women due to comorbidities, sociofamilial problems or difficulty to attend the radiotherapy sessions. Traditionally, whole-breast radiation therapy (WBRT) after surgery has been delivered over 5 weeks using a conventionally fractionated schedule (2 Gy daily) to a total dose of 50 Gy. This is a logistic issue, particularly for an elderly population, which affects radiotherapy accessibility and comprises a major determinant of its eventual underutilization. We need radiotherapy fractionation schedules adapted to elderly patients. Hypofractionation (HFRT) allows to administer a lower total dose delivered in fewer althought larger fractions. The objective of this study is to evaluate local control, acute and late toxicity and disease-free survival of elderly breast cancer patients treated with once- weekly adjuvant whole-breast radiation therapy. Material and Methods A consecutive series of 240 breast cancer elderly patients underwent once-weekly hypofractionated WBRT after breast conservative surgery, mastectomia or only biopsy , from January 2006 to September 2017. Patients were primarily selected to take into account older age, poor medical condition and/or logistic issues.They were given 32.5 Gy in 5 fractions (6.5 Gy once a week) until October 2011. Subsequently, they were administered 28,5 Gy in 5 fractions (5,7 Gy once a week).The modification of the fractionation to a lower dose per fraction was chosen according to the approach of the UK FAST randomized trial. Results The median aged was 78 years (35-89). 204 (85%) patients underwent breast-conserving surgery, 34 (14.2%) radical surgery and 2 (0.8%) no surgery.The clinical stage distribution was as follows: I in 92 (38.3%), II in 98 (40.8%), III in 49 (20.4%).Axillary lymph nodes were positive in 40.3 % of cases. Adjuvant hormonotherapy and chemotherapy was given in 83.3% and 16.7% respectively. There was no interruption of the treatment. Early skin reactions were tolerable. Late effects, mainly subcutaneous fibrosis, were recorded in 115 patients; they were classified as grade 1 in 94 cases, grade 2 in 24 cases and grade 3 in 7 patients (figure 1). No late toxicity in 115 patients. The patients with 32.5 Gy showed a worse cosmetic result

Conclusion According to the findings from this retrospective study, HFRT schedule is effective and well tolerated in the elderly patients,with toxicity equivalent to other schemes of radiotherapy treatment and with a high level of compliance.

Poster: Clinical track: Lung

PO-0768 High Heart Dose Affects Overall Survival in Lung Cancer Patients Undergoing Radiation Therapy. M. Fatyga 1 , S. Schild 1 , J. Niska 1 , M. Herman 2 , J. Li 3 , X. Liu 3 1 Mayo Clinic Arizona, Radiation Oncology, Phoenix, USA ; 2 Mayo Clinic Rochester, Radiation Oncology, Rochester, USA ; 3 Arizona State University, School of Computing- Informatics- Decision Systems Engineering, Tempe, USA

Purpose or Objective