ESTRO 36 Abstract Book

S162 ESTRO 36 _______________________________________________________________________________________________

Material and Methods This study was conducted within the Dutch UMBRELLA cohort (i.e. prospective observational cohort including breast cancer patients indicated to receive adjuvant radiotherapy at the department of Radiation Oncology at the University Medical Centre Utrecht). All participants consented to collection of clinical data and patient reported outcomes (PROMs). Arm function and Quality of Life (QoL) were measured by EORTC QLQ-C30 and BR23. We first compared differences in mean PROM scores between patients who underwent ALND and those who did not by two sample t-test. In a second step, we estimated the effect of extent of axillary radiotherapy on PROM scores in patients stratified on ALND, and used analyses of variance (ANOVA) to test for differences. Finally, we compared patients who underwent ALND and local RT with non-ALND patients treated with axillary RT to estimate the differences between axillary RT and ALND. Results Between October 2013 and December 2015, 521 patients were enrolled. In total 75% (n=390) of the patients were treated with local radiotherapy on the breast/chest wall (local RT), 10% (n=53) received additional axillary radiotherapy on level I and II (local RT + level I-II) and 15% (n=78) of the patients received local radiotherapy with axillary irradiation including levels III and IV (local RT + level I-IV) (Table 1). ALND (n=84) was performed in 10% (n=40) of the patients in the local RT group and in 56% (n=44) of the locoregional RT group (Table 1). Patients in the ALND group reported significantly lower arm function compared to the non-ALND group (Figure 1A-B). For patients who underwent ALND and local RT, arm symptoms were significant worse at baseline and 3 months compared to non-ALND patients who received local RT and axillary (level I-II or level I-IV) irradiation (MD -15.2, p=0.00 and - 13.4, p=0.00) (Figure 1C). Overall QoL scores were similar.

Conclusion Arm function in patients treated with ALND was worse compared to patients without ALND. Patients reported significant more arm symptomatology after ALND followed by local RT compared to non-ALND patients treated with local RT and axillary irradiation in the first 3 months after start of RT. Updated results on PROMs with increased patient numbers, longer follow-up and multivariable analyses will be available at the 36 th ESTRO conference. SP-0314 Partial breast radiotherapy after breast conservation: 5 year outcomes from the IMPORT LOW (CRUK/06/003) phase III trial C. Coles 1 , C. Griffin 2 , A. Kirby 3 , R. Agrawal 4 , A. Alhasso 5 , I. Bhattacharya 2 , A.M. Brunt 6 , L. Ciurlionis 7 , H. Chan 8 , E. Donovan 3 , M. Emson 2 , A. Harnett 9 , J. Haviland 2 , P. Hopwood 2 , M. Jefford 10 , R. Kaggwa 2 , E. Sawyer 11 , I. Sybdikus 12 , Y. Tsang 13 , D. Wheatley 14 , M. Wilcox 15 , J. Yarnold 16 , J. Bliss 2 1 Cambridge Cancer Centre, University of Cambridge, Cambridge, United Kingdom 2 Clinical Trials and Statistics Unit, Institute of Cancer Research, London, United Kingdom 3 Royal Marsden NHS Foundation Trust, Department of Radiotherapy, London, United Kingdom 4 Shrewsbury and Telford Hospitals NHS Trust, Oncology Department, Shrewsbury, United Kingdom