ESTRO 2020 Abstract Book

S512 ESTRO 2020

PO-0958 Neoadjuvant RT followed by mastectomy and immediate breast reconstruction: updated 5-years results M. Pazos 1 , D. Dian 2 , S. Schönecker 1 , D. Reitz 1 , A.M. Schäfer 1 , D. Konnerth 1 , R. Würstlein 3 , N. Harbeck 3 , C. Belka 1 , S. Corradini 1 1 LMU Munich, Radiotherapy, Munich, Germany ; 2 KLinik Mednord, Department of Gynecologic surgery, Munich, Germany ; 3 Breast Center- LMU Munich, Gynecology, Munich, Germany Purpose or Objective Neoadjuvant radiotherapy aims to improve the aesthetic results and simplify the reconstructive pathway in the treatment of locally advanced breast cancer (LABC) patients before mastectomy. A series of 22 patients was published in 2017 with a median follow up of 30 months. Here we present the updated 5-year results. Material and Methods Between 04/2012 and 03/2015 overall 22 patients diagnosed with LABC were treated with neoadjuvant radiotherapy followed by mastectomy and IBR. RT consisted of external beam radiotherapy to the breast and the regional lymphatics, if indicated: 91% 3D-Plans, 9% VMAT (including parasternal region). Patient characteristics: 45% had no prior surgery, 55% had previously undergone R1-breast-conserving surgery (BCS). Neoadjuvant chemotherapy had been given in 82% of the patients, 4 patients also received anti-Her-2-neu therapy. Both implant-based and autologous tissue-transfer reconstruction techniques were used. Two patients refused mastectomy after radiotherapy and were not assessed for cosmetic analysis. The cosmetic results were assessed at each medical visit evaluating volume, contour, symmetry, scars and the inframammary fold of the reconstructed breast. Each parameter was scored from 0 to 2 points. The results were simplified as follows: 10-8 points=excellent; 7-6 points=good; 5-4 points=fair; fewer than 4 points=poor. Results The median follow-up was 60 months (4-78 months). A complete pathological response was achieved in 55.0% of patients. The published 2-year data were: overall survival (OS) 89%, disease free survival (DFS) 80% and local- recurrence-free survival (LRFS) 95%. The 5-year data changed to: OS 82%, DFS 77% and LRFS 91%. Among all patients who received implant-based IBR, 5 patients developed serious wound-healing problems with implant loss, 4 of them in the first 2 years after the IBR and one patient later on. The cosmetic results were excellent or good at 2-years in 66% of the patients treated with upfront mastectomy and 36% of the patients who had previously undergone BCS. After 5-years, cosmetic results remained similar, although 3 patients needed re-operations because of contractures (1 pat), implant implant rupture (1 patient) and lipofilling (1 pat). The most satisfactory results continued to be achieved with autologous-tissue reconstruction. Conclusion After mean follow-up of 5 years, the neoadjuvant chemo- /radiotherapy concept for LABC achieves very similar results as at 2-years-follow-up. Careful patient selection is mandatory to achieve a good oncological and cosmetic success using this treatment strategy. PO-0959 Treatment outcomes of breast cancer lung metastasis treated with stereotactic body radiotherapy O.C. Güler 1 , S.Y. Sari 2 , M. Gultekin 2 , B.A. Yıldırım 3 , O. Ozyılkan 4 , F. Yıldız 2 , C. Onal 3 1 Baskent Universitesi Tip Fakultesi- Adana Hastanes, Radiation Oncology, Adana, Turkey ; 2 Hacettepe University, Radiation Oncology, Ankara, Turkey ; 3 Baskent University, Radiation Oncology, Adana, Turkey ; 4 Baskent University, Medical Oncology, Adana, Turkey

Purpose or Objective To analyze the outcomes of breast cancer lung metastasis (BCLM) treated with stereotactic body radiotherapy (SBRT) and systemic treatment. Material and Methods The treatment outcomes of 19 patients with oligometastasis (<5 metastases) at the time of lung metastasis (LM) or who became oligometastatic after systemic treatment were assessed. A total of 23 LM’s were treated with SBRT with a median 3 fractions (range, 3-10 fractions) to a total dose of 60 Gy (range, 30-60 Gy) between May 2011 and February 2019. The local control (LC), overall survival (OS), and progression-free survival (PFS) rates were calculated using Kaplan-Meier analyses. Results Median age and follow-up time were 47 years (range 32 – 76 years) and 14.5 months (range 1.1 – 49.9 months), respectively. Among 19 patients, 16 (84%) had solitary LM while 2 patients (11%) had two lesions and 1 patient (5%) had three lesions. Estrogen receptor (ER) and progesterone receptor (PR) were positive in 12 patients (52%) and 8 patients (35%), respectively. All patients had mastectomy for primary disease, and 17 patients (89%) received postoperative adjuvant chemotherapy and radiotherapy, while 2 patients (17%) had adjuvant chemotherapy only. Most of the patients [17 patients (89%)] developed LM during the follow-up of initial treatment, while only 2 patients (11%) had LM at the time of first diagnosis. At last visit, 11 patients (58%) had disease recurrence, median 8.4 months (range 3 – 16.3 months) after completion of liver SBRT. Only 5 patients (26%) had local recurrences. Median OS and PFS were 19.1 months [95% confidence interval (CI) 11.2 – 26.9 months]) and 8.3 months (95% CI; 7.9 – 8.8 months), respectively. The 1-year LC and OS rates were 49% and 82%, respectively. Conclusion This study is the first to evaluate the feasibility of SBRT to BCLM patients in a larger patient cohort. Our findings support that the lung SBRT is a feasible and safe method for BCLM with excellent LC and acceptable toxicities. PO-0960 Metastatic breast cancer – Survival impact of locoregional treatment C.A.D.N. Laranja 1 , F. Sousa 1 , I. Rodrigues 1 , B. Castro 1 , I. Azevedo 1 , J. Conde 1 , V. Castro 1 , N. Stas 1 , H. Pereira 1 1 Instituto Português de Oncologia do Porto, Radioterapia externa, Porto, Portugal Purpose or Objective Purpose/Objective: Breast cancer is one of the most common cancers worldwide among women. Stage IV presentation at diagnosis involves only 3-8% of patients. The associated survival at this stage, may vary from months to years, however the prognosis is always reserved. The recommended therapeutic approaches rely mainly on systemic treatment, reserving locoregional treatment (LRT), namely radiotherapy (RT) and surgery, for palliative interventions related to the evolution of the disease. Some studies, however, have suggested a benefit of LRT of the primary tumor in clinical outcomes. The aim of this study, was to assess the impact of LRT on breast cancer patients presenting with stage IV at diagnosis in terms of OS and PFS. Material and Methods Material and methods: Retrospective analysis of 198 cases diagnosed with de novo stage IV breast cancer, treated at our institution between January 2013 and December 2017. Patients were divided in two groups those who underwent LRT of the primary tumor plus systemic therapy (LRT group) and those who only received systemic therapy (no- LRT group). Among those undergoing LRT, sub-groups where created: patients undergoing surgery, RT or surgery plus RT. Progression free survival (PFS) and overall survival (OS) were investigated. Statistical analysis was conducted using SPSS version 24.