ESTRO 38 Abstract book

S698 ESTRO 38

EP-1271 Effects of regular bra-wearing on acute skin toxicity in breast-conserving radiotherapy women P. Thongkhao 1 , T. Peerawong 1 , R. Jiratrachoo 1 , J. Pruetkitti 1 , A. Geater 2 1 Faculty of Medicine- Prince of Songkla University., Radiology, Hat Yai- Songkhla, Thailand ; 2 Faculty of Medicine- Prince of Songkla University., Epidemiology Unit, Hat Yai- Songkhla, Thailand Purpose or Objective At present, the instruction of wearing bra in daily life during radiotherapy treatment course in breast conserving therapy (BCT) patients is unclear. This study aimed to evaluate the effect of regular bra-wearing during radiotherapy on acute skin toxicity and the quality of life in women with BCT . Material and Methods This study is a preliminary prospective non-inferiority cohort study . Women with any stage breast cancer who underwent BCT were enrolled from June 2017 to July 2018 at a single tertiary center in the Southern Thailand . The exclusion criteria included patients who underwent an immediate reconstruction, patients with pre-existing skin lesions in the treatment area, and patient with known systemic skin diseases, even not directly affecting irradiated fields. After informed consent was obtained, participants were instructed to wear appropriate bra, record the hours per day of wearing bra in a patient record form, and were told they could freely decide to wear the bra or not. Then all participants were classified by total hours of wearing bra during the radiotherapy treatment course into non-bra-wearing (0 hr.) and bra-wearing groups (>0 hr.). The acute skin toxicity was assessed weekly and one week after treatment end by CTCAE version 4 and the quality of life was assessed before and one week after treatment end by FACT-B Thai version 4. All participants were treated with a dose of 50Gy in 25 fractions over 5 weeks. An addition boost 10-16Gy was given, depending on clinical judgement. Differences in acute skin toxicity grade between the two groups were assessed using Chi-square test or a Fisher’s exact test and the quality of life scores were compared using Student’s t-test or Wilcoxon rank- sum test. Results A total of 99 patients were eligible, which 66 patients were in bra-wearing group and 33 patients were in non- bra-wearing group. Baseline patient characteristics were well balanced except for T-stage and median maximum dose. Overall rate of ≥ G2 acute skin toxicity was 29% and began to appear after 4 th week of treatment in both groups (Figure 1). The rate of ≥ G2 acute skin toxicity was lower in bra-wearing group compared to non-bra-wearing group (16.7% vs. 54.5%, p<0.001, respectively) . In the multivariate analysis, the statistically significant factors that associated with increased the risk of ≥ G2 acute skin toxicity were non-bra-wearing (0 hr.) (p<0.001), high body mass index (p=0.002), and high percentage of maximum dose (p=0.022) (Table 1). There was no difference in all five parts and total mean scores of after treatment FACT- B Thai between the bra-wearing and non-bra-wearing groups (118.4 vs. 114.7, p=0.256, respectively).

Conclusion Regular bra-wearing during radiotherapy is not associated with increased the risk of ≥ G2 acute skin toxicity and does not affect the quality of life compared to non-bra- wearing. EP-1272 Is hypofractionated nodal radiotherapy safe in the treatment of breast cancer patients? C. Matthieu 1 1 CHU, Radiotherapy, BESANCON, France Purpose or Objective We retrospectively evaluated safety and efficacy of hypofractionated locoregional radiotherapy (HLRT) in breast cancer (BC) patients. We compared them patients treated, in the same period, with hypofractionated radiotherapy on the breast/wall chest only (HRT). Material and Methods We reviewed the charts of patients with biopsy-proven BC treated with postoperative HLRT (n= 275, 63%) or HRT (n= 160, 37%) between 2008 and 2011. Incidence of acute and late toxicity was the primary endpoint. Five-year locoregional-free survival (LRR-FS), disease-free survival (DFS) and overall survival (OS) were also analyzed and reported. Results Median follow-up was 61.7 months. Treatment was globally well-tolerated. Severe acute toxicity was found in 4.4% of the HRT cohort and 3.1% of the HLRT one (p=0.79), usually as dermatitis. HLRT patients presented more frequently G1-2 dysphagia (30.6% vs 0.4%, p<0.001) and/or G1-2 lymphedema (5.6% vs 0.4%, p=0.002). At multivariate analysis, tabagism was the only independent factor statistically influencing the risk of acute toxicity (p=0.047). Concerning late toxicity, HLRT patients presented more frequently G1-2 lymphedema (6.2% vs 0.7%, p=0.003). Five-year LRR-FS was 96.3% in the HRT and 92% in the HLRT population, respectively (p=0.004). Five- year DFS was 92.2% in the HRT and 83.4% in the HLRT population, respectively (p=0.004). Five-year OS was 96.4% in the HRT and 92.6% in the HLRT group, respectively (p=0.027).