ESTRO 37 Abstract book

S701

ESTRO 37

Rivero 2 , A. Corbacho 2 , Y. Ríos Kavadoy 2 , J.J. Cabrera Rodriguez 2 1 Hospital Infanta Cristina, Oncology Radiotherapy, utrera, Spain 2 Hospital Infanta Cristina, Oncology Radiotherapy, Badajoz, Spain Purpose or Objective The presence of positive margins after conservative treatment in breast cancer is a prognostic factor of local recurrence. The objective of our study was to e valuate the relationship between margin status and local relapse after breast conserving therapy (BCT). Material and Methods Retrospective analysis of 1143 out of 1205 patients (pts) who underwent BCT (stage I-II) from January 1995 to December 2012. The median age was 58 years (27-92). 62% were T1 and 38% T2. 63% was luminal A. 67% received Chemotherapy (CT) and 84% Hormonotherapy (HT). Surgical margin was negative (≥2mm) in 88% (NM), positive in 5% (PM), and close (<2 mm) in 6% (CM). Median bed tumour total dose was 60 Gy with NM, 66 Gy with CM, and 70 Gy with PM. Survival rates were estimated with Kaplan-Meier and compared with Log Rank test. Prognostic factors such as age, biological subtype, tumour stage, grade, total dose RT, HT and CT have been related to local disease free survival (LDFS) and overall survival (OS) using Cox regression. Results At a median follow-up of 109 months (5-255). Local recurrence as first site of failure was present in 22 pts (2.2%) with NM, 2 pts (2.8%) in CM and 2 pts (3.3%) in PM. 8-Year LDFS and OS were 99.7% and 89.3% in pts with NM, 98.3% and 89.9% in CM and 96.1% and 85% in PM respectively. In the multivariate analysis only molecular subtype triple negative was a significant prognostic factor of LDFS (p=0.008) and biological subtype HER2 (p=0.005), age ≥66 years (p=0.000) and tumor stage T2 (p=0.032) were a significant prognostic factor of OS. Conclusion Regarding our results, local relapse as the first site of failure is infrequent in early breast cancer after conserving therapy even in patients with close or positive surgical margins. EP-1272 Stereotactic Body Radiotherapy for Oligometastatic and Oligoprogressive Disease C. Pembroke 1 , B. Fortin 2 , N. Kopek 3 1 Velindre Cancer Centre, Radiation Oncology, cardiff, United Kingdom 2 Hospital Maisonneuve Rosemont, Radiation Oncology, Montreal, Canada 3 McGill University Health Centre, Radiation Oncology, Montreal, Canada Purpose or Objective Clinical challenges arise as the use of targeted and immunotherapies results in patients living longer with metastatic disease. The use of stereotactic radiotherapy (SBRT) in treating oligometastases (OM) has been shown in many retrospective series to be a safe and effective treatment modality. An oligoprogressive (OP) state occurs when single lesions progress on a background of widespread but stable disease and ablative strategies are increasingly used with very little evidence to support a therapeutic benefit. The purpose of this study is report on and compare outcomes and prognostic variables for patients with OM and OP disease treated with SBRT at a single Canadian institution. Material and Methods A retrospective review of patients treated with extracranial metastatic disease treated with SBRT between 2007 and June 2016. OM was defined as those patients with 5 lesions or less where all sites of disease

were treated with ablative strategies whereas the OP group had only the progressing lesions treated. Results 163 metastatic patients treated for 209 lesions, 106 were treated in the OM group and 57 treated in the OP group. The median overall (OS) and progression free survivals (PFS) were 37 and 15 months versus 21.7 and 6.4 months in the OM and OP groups respectively (P=0.02 and P=0.01). Multivariate analysis demonstrated performance status (0/1 vs 2 HR 2.95) and number of metastases (1/2 vs 3 HR 1.88) were independent prognosticators for survival.The OM group had a 1 and 2-year disease free survivals of 55 and 25% respectively versus 22% and 6% in the OP cohort (P<0.001). Patterns of first relapse demonstrated four times higher risk of recurrence outside the irradiated field with a higher risk according to OP status (p=0.03), 3 or more metastases (p=0.002) and concurrent chemotherapy (p=0.001). Conclusion This retrospective review of a large cohort of metastatic patients treated with SBRT shows inferior OS and PFS when comparing the OP and OM groups respectively. Poor performance status and higher burden of disease (3 lesions) are independent prognosticators for survival. The majority of OP patients relapsed within their first year following treatment with the majority of these occurring outside the irradiated field. Prospective randomised data is required to be able to quantify the true benefit to these patients and to assess prognostic variables to help guide patient selection. EP-1273 Creation of an Educational Quality Improvement Program for Radiation Oncology Residents C. Pembroke 1 , J. Alfieri 2 , A. Biron 3 , C. Freeman 2 , T. Hijal 2 1 Velindre Cancer Centre, Clinical Oncology, cardiff, United Kingdom 2 McGill University Health Centre, Radiation Oncology, Montreal, Canada 3 McGill University, School of Nursing, Montreal, Canada Purpose or Objective Quality Improvement (QI) is a pillar of good clinical governance and is at the center of modern health care. The Royal College of Physicians and Surgeons of Canada mandated, in CanMeds 2015, that QI should be taught and the competencies assessed in all post-graduate residency programs. The objective is to report on the feasibility and impact of teaching QI to radiation oncology residents A QI team consisting of a clinical fellow and 3 staff physicians as well as an expert in QI methods was created within the Department of Radiation Oncology. QI teaching took place in a longitudinal manner with approximately 12 hours of direct faculty teaching. A mandatory curriculum divided into foundation, and intermediate and advanced competencies was devised. Phase 1 teaching, delivered during two academic half days, consisted of didactic lectures, practical workshops and self-directed online modules. Phase 2 required intermediate year residents to complete a nine-month QI project. A QI day hosted by the Department invited QI experts to teach and enabled residents to present their work with merit prizes awarded. Our program evaluation used validated assessment tools (self-assessment, QI-knowledge based assessments (QI-KATs), and balanced score cards) before and after curriculum implementation. Learners attitudes were assessed anonymously using a 6-question questionnaire scored on a Likert scale where answers were quantified using satisfaction indices (SI). Results Subjective and objective assessments demonstrated improvements in resident’s QI knowledge acquisition following curriculum implementation. Mean QI-KAT scores increased from 4.3 to 7.8 pre and post phase 2 at a single institution. Material and Methods