ESTRO 2021 Abstract Book

S44

ESTRO 2021

social functioning were measured prior to, during, and after the LRT survey using EORTC QLQ-C30 and the thresholds for clinical importance (i.e. indicating clinically relevant impairment). Results 763/1048 patients (73%) responded to the LRT survey. After a median follow up of 44 months (range 12-71), 17% (n= 129) reported LRT. Moderate/severe breast or chest wall pain was reported by 138/763 (18%) patients and moderate/severe firmness of the breast was reported by 139/759 (18%) patients (Figure 1). Of all patients with LRT, 38-53% functioned below the clinical threshold for physical functioning compared to 21-27% of patients without LRT (Figure 2). A higher proportion of patients with LRT (23-43%) scored below the threshold for role functioning when compared to patients without LRT (7-21%). Patients with self-reported LRT significantly more often received analgesics, physiotherapy and lymphedema therapy compared to patients without LRT. Figure 1. Prevalence of self-reported symptoms of late radiation skin toxicity in breast cancer patients (n=755- 763).

Figure 2. Proportion of breast cancer patients with and without self-reported symptoms of late radiation skin toxicity who function below the clinical relevant EORTC QLQ-C30 thresholds immediately after surgery (i.e. baseline), prior to, during and after the late radiation toxicity questionnaire in comparison to a Dutch normative population.

Time: Baseline = upon cohort inclusion; T-1 = standard UMBRELLA cohort questionnaire before the late radiation toxicity questionnaire; T0= at the moment of the late radiation toxicity questionnaire; T+1= standard UMBRELLA cohort questionnaire after the late radiation toxicity questionnaire. The Dutch normative population comprised 860 women without any cancer diagnosis with comparable age to our study population. Clinically relevant thresholds, i.e., based on Giesinger et al, for the EORTC QLQ-C30 domains are 83 for physical functioning, 58 for social functioning and 58 for role functioning. Conclusion LRT was reported by 17% of the patients, and these patients reported lower scores for physical, role and social functioning compared to patients without LRT. OC-0071 Safety and efficacy of concomitant radiation and CDK4/6 inhibitors in breast cancer patients L. Visani 1 , I. Ratosa 2 , E. Scoccimarro 1 , C. Becherini 1 , C. Saieva 3 , I. Desideri 1 , V. Scotti 1 , M. Ozarem 2 , D. Ribnikar 2 , M. Aquilano 1 , C. Cerbai 1 , L. Orzalesi 4 , M. Bernini 4 , L. Sanchez 4 , J. Nori 5 , S. Bianchi 6 , I. Meattini 1 , L. Livi 1 1 University of Florence, Department of Experimental and Clinical Biomedical Sciences, Florence, Italy; 2 Institute of Oncology Ljubljana, Division of Radiation Oncology, Ljubljana, Slovenia; 3 Cancer Research and Prevention Institute, Molecular and Nutritional Epidemiology Unit, Florence, Italy; 4 Azienda Ospedaliero- Universitaria Careggi, Breast Surgery Unit, Florence, Italy; 5 Azienda Ospedaliero-Universitaria Careggi, Diagnostic Senology Unit, Florence, Italy; 6 University of Florence, Pathology Unit, Florence, Italy