ESTRO 2025 - Abstract Book

S629

Clinical - Breast

ESTRO 2025

3. Waljee, J.F., et al., Effect of esthetic outcome after breast-conserving surgery on psychosocial functioning and quality of life. J Clin Oncol, 2008. 26(20): p. 3331-7

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Mini-Oral Breaking Barriers in Breast Cancer Trials: Non-Accrual Insights from the phase III randomized clinical DBCG NATURAL and PROTON trials Bjarke Godske Baisner 1,2 , Louise Wichmann Matthiessen 3 , Else Maae 4 , Mette Møller 5 , Maja V. Maraldo 6 , Sami Al Rawi 7 , Susanne Oksbjerg Dalton 8,9,10 , Cai Grau 2,11 , Birgitte Vrou Offersen 1,2,12 1 Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark. 2 Department of Clinical Medicine, Aarhus University, Aarhus, Denmark. 3 Department of Oncology, Copenhagen University Hospital Herlev and Gentofte,, Copenhagen, Denmark. 4 Department of Oncology, Vejle Hospital, University Hospital of Southern Denmark, Vejle, Denmark. 5 Department of Oncology, , Aalborg University Hospital, Aalborg, Denmark. 6 Department of Oncology, University Hospital of Copenhagen, copenhagen, Denmark. 7 Department of Oncology, Næstved Hospital, Næstved, Denmark. 8 The Danish Cancer Institute, The Danish Cancer Institute, Copenhagen, Denmark. 9 Department of Clinical Oncology and Palliative Care, Zealand University Hospital, Næstved, Denmark. 10 Institute of Clinical Medicine, Faculty of Health, Copenhagen University, Copenhagen, Denmark. 11 Danish Center for Particle Therapy, Aarhus University Hospital, Aarhus, Denmark. 12 Department of Oncology, Aarhus University Hospital, Aarhus, Denmark Objectives : Annually, 5000 Danish patients are diagnosed with breast cancer (BC) (1) . The Danish Breast Cancer Group (DBCG) provides guidelines for standard adjuvant radiotherapy (2) and develops new radiotherapy strategies through trials (3-6). Trial participation may vary due to patient, socio-economic, and geographic barriers as well as barriers related to healthcare professionals, including preferences and lack of time. This study, supported by the Danish Clinical Quality Improvement Program, Danish Comprehensive Cancer Center, and the Danish Cancer Society, examined reasons for non-inclusion in the phase III randomized DBCG NATURAL and PROTON trials. Methods : From September 2021 to December 2023, a screening log recorded non-trial participation reasons across all Danish radiotherapy departments. Each patient file was reviewed to determine reasons for not being included in the trial. The DBCG Natural trial included selected relatively low-risk BC patients ≥60yr to be randomized to partial breast irradiation versus no irradiation. The DBCG Proton trial selected patients on high radiation dose to heart and/or lung and randomized between photon versus proton radiotherapy. Exclusion criteria were previous BC/DCIS/other malignancies and bilateral disease (Natural trial). Results : Non-inclusion rates for the NATURAL Trial varied in four recruiting departments. Overall, 559 patients were candidates for trial, and 301 patients were not included, corresponding to 54%-79% of the eligible patients not accrued per center. The key reasons for omitting trial were patient preference (75%), eligibility not mentioned in the multidisciplinary team meetings and/or the physician did not discuss trial with the patient (16%) with a variation across centres ranging from 0%-11%, and other reasons (8%). There was some variation in the likelihood of being offered trial; some departments offered the trial to virtually all eligible patients, whilst other departments missed the opportunity. For the PROTON Trial, 215 patients with high heart and/or lung doses were identified. Rates of not accruing these patients at 6 departments were 40%-79%. Reasons were patient preference (49%), geographic barriers (24%), language barriers (8%), doctors’ preference (6%), comorbidity (4%) and other reasons (8%).

Conclusion : The marked variations across centres suggest a need for standardised patient information on trial benefits and a