EJC Vol. 92 Supplement 3

Conclusions: Hypofractionated VMAT treatment with SIB after breast conservative surgery in patients undergone adjuvant systemic therapy was safe and well tolerated in terms of acute and early late settings. Cosmetic results were also good or excellent in the most of patients. Long-term follow- up data are needed to assess late toxicity and clinical outcomes. No conflict of interest 229 (PB-024) Poster Acute toxicity and quality of life in breast cancer patients treated by radiotherapy – results from the REQUITE multi-centre cohort study T. Rattay 1 , K. Johnson 1 , D. Azria 2 , J. Chang-Claude 3 , S. Davidson 4 , A. Dunning 5 , D. De Ruysscher 6 , S. Gutierrez-Enriquez 7 , P. Lambin 6 , T. Rancati 8 , B. Rosenstein 9 , P. Seibold 10 , R.P. Symonds 1 , R. Valdagni 8 , A. Vega 11 , L. Veldeman 12 , A. Webb 13 , F. Wenz 14 , C. West 15 , C. Talbot 13 . 1 University of Leicester, Leicester Cancer Research Centre, Leicester, United Kingdom; 2 ICM Institut du Cancer, Radiotherapy, Montpellier, France; 3 DKFZ German Cancer Research Centre, Epidemiology of Cancer, Heidelberg, Germany; 4 The Christie Hospital NHS Foundation Trust, Radiotherapy, Manchester, United Kingdom; 5 University of Cambridge, Centre for Cancer Genetic Epidemiology, Cambridge, United Kingdom; 6 Maastro Clinic, Radiotherapy, Maastricht, Netherlands; 7 Vall d ’ Hebron Institute of Oncology, Oncogenetics, Barcelona, Spain; 8 Fondazione IRCCS Istituto Nazionale dei Tumori, Prostate Cancer Program, Milan, Italy; 9 Icahn School of Medicine at Mount Sinai, Radiation Oncology, New York City, United Kingdom; 10 DKFZ German Cancer Research Institute, Epidemiology of Cancer, Heidelberg, Germany; 11 Fundacion Publica Galega Medicina Xenomica, Genomic Medicine, Santiago de Compostela, Spain; 12 University Hospital of Gent, Radiotherapy, Gent, Belgium; 13 University of Leicester, Genetics and Genome Biology, Leicester, United Kingdom; 14 University Medical Centre Mannheim, Radiotherapy, Mannheim, Germany; 15 University of Manchester, Division of Cancer Sciences, Manchester, United Kingdom Background: Although patient-reported outcomes (PROs) to assess health- related quality-of-life (QoL) are increasingly incorporated in radiotherapy trials, QoL in the acute period following treatment remains under-reported. This study assessed the relationship between QoL in the acute treatment phase with acute radiotherapy toxicity and patient and treatment variables in breast cancer patients. Methods: Breast cancer patients (n = 2,071) were recruited following breast-conserving surgery across eight centres in Europe and North America into a multicentre prospective cohort study (www.requite.eu ). Treatment data, toxicity scored according to CTCAE v4.0, and PROs from EORTC- QLQ-C30 and – B23 were available for 1,750 patients at baseline and on completion of radiotherapy. Association of worsening QoL ( ≥ 10 point change from baseline, dichotomised) with acute toxicity, patient and treatment variables was investigated using mixed effects logistic regression. Results: By the end of radiotherapy, 24.2% of patients experienced ≥ grade 2 erythema, 31.6% ≥ grade 1 oedema, and 9.5% were affected by acute desquamation (skin loss). Overall QoL (global health status), fatigue, pain, and breast symptoms worsened significantly compared to baseline. Worsening breast symptoms were significantly associated with acute erythema (OR 1.74, 95% CI 1.43 – 2.18), acute desquamation (1.77, 1.18 – 2.67), radiotherapy dose including boost (1.04, 1.02 – 1.06 per Gy BED), and alcohol use (1.31, 1.04 – 1.64), while worsening pain was associated with acute erythema (1.24, 1.03 – 1.50) and increasing BMI (1.04, 1.02 – 1.06 per unit BMI). There was no significant association of any acute toxicity endpoint with worsening global health status or fatigue. Worsening QoL (global health status) was associated with chemotherapy (1.77, 1.29 – 2.44), while alcohol use was inversely associated (0.62, 0.46 – 0.82). Worsening fatigue was associated with increasing BMI (1.02, 1.00 – 1.05) and alcohol use (1.32, 1.06 – 1.65) in this cohort. Conclusions: Management of early toxicities that affect breast-specific symptoms and pain may improve QoL during radiotherapy. Overall QoL (global health status) and fatigue during breast radiotherapy is likely to be influenced by a range of non-radiotherapy treatment and patient factors. No conflict of interest 230 (PB-025) Poster What is the effect of axillary treatment and irradiated volumes on patient reported outcome measures in breast cancer patients? M. Gregorowitsch 1 , H. Verkooijen 2 , N. Fuhler 1 , D. Young Afat 1 , A. Kotte 1 , A. Houweling 1 , D. Van den Bongard 1 . 1 UMC Utrecht, Radiotherapy, Utrecht, Netherlands; 2 UMC Utrecht, Imaging Division, Utrecht, Netherlands In breast cancer patients with limited sentinel lymph node involvement, axillary lymph node dissection (ALND) is replaced by axillary radiotherapy (RT), in order to reduce the risk of upper-body morbidity without compromising breast cancer recurrence rates. Radiation, however can also cause morbidity, the extent of which depends on the irradiated target volumes. We compared patient reported outcome measures (PROs) before, during and after RT according to the extent of axillary treatment. This study was conducted within the UMBRELLA cohort, i.e. prospective observational cohort including breast cancer patients indicated to receive post-operative RT at the department of Radiation Oncology at the University Medical Center Utrecht. PROs (arm symptoms and quality of life (QOL)) were assessed with the EORTC QLQ-C30/BR23 before start of RT at 3 months and every 6 months thereafter for the course of 36 months. We compared PROs between treatment groups over time, using linear mixed models adjusting for age, time, type of surgery. Patients treated with local RT on the breast/chest wall (local RT), local RT with additional RT on level I and II of the axilla (local RT + level I-II) and local RT with axillary irradiation including axillary levels I-IV (local RT + level I-IV) were compared. The effect of ALND vs. axillary RT was assessed by comparing patients treated with ALND and local RT to patients with local RT + levels I-II/IV. Of the 1,065 eligible patients, 971 (91%) responded to at least one questionnaire and were selected. The majority of patients (78%) was diagnosed with a tumor up to 5cm (T1,T2) and 76% without lymph node involvement (N0). In total 74% (n = 715) of the patients were treated with local RT, 10% (n = 96) received local RT + axillary RT on level I-II and 16% (n = 160) received local RT + axillary RT on level I-IV. In the local RT group 58 (8%) patients received ALND and 82 (51%) in the local RT + level I-IV group. Arm symptoms in the local RT group were significant less common at 6, 12 and 18 months compared to the local RT + level I-II group. Compared to the local RT + level I-IV patients, arm symptoms of patients treated with local RT were also significant less common at baseline and 3 months. Arm symptoms were comparable in between patients who received local RT + level I-II and local RT + level I-IV. Patients treated with ALND and local RT reported significant more arm symptoms in the first 3 months compared to non-ALND patients treated with axillary RT (level I,II or level I-IV). QOL was similar between patients with ALND + local RT and non-ALND patients treated with axillary RT. Arm symptoms were more common after ALND followed by local RT compared to patients with axillary irradiation only at 3 months after start of RT. Compared to local RT group only, locoregional RT groups reported more arm symptoms. However, this did not affect QOL. No conflict of interest 231 (PB-026) Poster Short-term efficacy and toxicity after single dose ablative pre-operative partial breast radiotherapy J. Vasmel 1 , R. Charaghvandi 1 , A. Houweling 1 , M. Philippens 1 , P. Van Diest 2 , G. Van Leeuwen 3 , J. Van Gorp 4 , A. Witkamp 5 , C. Van der Pol 5 , R. Koelemij 6 , A. Doeksen 6 , E. Theunissen 6 , T. Van Dalen 7 , E. Van der Wall 8 , I. Van Dam 1 , W. Veldhuis 9 , H. Verkooijen 10 , D. Van den Bongard 1 . 1 UMC Utrecht, Radiation oncology, Utrecht, Netherlands; 2 UMCUtrecht, Pathology, Utrecht, Netherlands; 3 st. Antonius, Pathology, Nieuwegein, Netherlands; 4 Diakonessenhuis, Pathology, Utrecht, Netherlands; 5 UMC Utrecht, Surgery, Utrecht, Netherlands; 6 st. Antonius, Surgery, Nieuwegein, Netherlands; 7 Diakonessenhuis, Surgery, Utrecht, Netherlands; 8 UMC Utrecht, Medical Oncology, Utrecht, Netherlands; 9 UMC Utrecht, Radiology, Utrecht, Netherlands; 10 UMC Utrecht, Imaging Division, Utrecht, Netherlands Background: To evaluate feasibility of single dose ablative pre-operative partial breast radiotherapy (RT) in patients with low-risk breast cancer. Material and Methods: Women with low-risk breast cancer were included in a pre-operative partial breast RT trial with pathologic complete response (pCR) as primary outcome. Patients with unifocal tumors T1 – 2(max 3cm) and negative sentinel node, fulfilling the ESTRO criteria for partial breast RT, underwent single dose ablative partial breast RT(1×20/15Gy to tumor/tumor bed) followed by breast-conserving surgery (BCS) after 6 months. Treatment-induced toxicity was scored according to Common Terminology Criteria for Adverse Events (CTCAE) 4.03. Quality of Life (QoL), anxiety and depression were evaluated by validated questionnaires at baseline, at 6 and 12 months after RT. Cosmetic questionnaires were filled out at the same intervals and at 2 months following RT. Results: Between January 2015 and January 2017, 15 patients were treated with single dose ablative pre-operative partial breast RT. Two patients received additional neoadjuvant hormonal therapy. Median follow-up was 12 months (range 9 – 24 months). In 5 patients(33%) pCR was observed, in 5 patients(33%) near pCR. Transient RT-induced grade 2 toxicity was seen in 3 patients. One patient developed postoperative wound infection (table 1). European Journal of Cancer 92, Suppl. 3 (2018) S17 – S160 S60 Abstracts, EBCC 11 Poster Session (Thursday, 22 March 2018)