ESTRO 2023 - Abstract Book

S626

Monday 15 May 2023

ESTRO 2023

Conclusion Moderately HF loco-regional RT is non-inferior to NF RT in terms of lymphedema risk in EBC. Together with the Skagen 1 trial, this study provides level 1A evidence supporting the use of 40 Gy/15 fr for loco-regional radiation therapy in EBC with respect to arm lymphedema risk.

OC-0759 Shared Decision Making with breast cancer patients - does it work? The randomized DBCG RT SDM trial S. Rauff Søndergaard 1 , T. Bechmann 2 , B. Vrou Offersen 3 , A. WM Nielsen 3 , M. Holck Nielsen 4 , M. Møller 5 , L. L. Berry 6 , R. Zachariaee 7 , K. Dahl Steffensen 8 1 Lillebaelt Hospital – University Hospital of Southern Denmark, Department of Oncology, Vejle, Denmark; 2 Regional Hospital West, Department of Oncology, Herning, Denmark; 3 Aarhus University Hospital, Department of Experimental Clinical Oncology & Department of Oncology, Aarhus, Denmark; 4 Odense University Hospital, Department of Oncology, Odense, Denmark; 5 Aalborg University Hospital, Department of Oncology, Aalborg, Denmark; 6 College Station, Texas A&M University, Texas, USA; 7 Aarhus University, Department of Psychology and Behavioral sciences, Aarhus, Denmark; 8 Lillebaelt Hospital – University Hospital of Southern Denmark, Center for Shared Decision Making, Vejle, Denmark Purpose or Objective Shared decision making (SDM) is a patient-engaging process and is especially advocated for preference-sensitive decisions, such as adjuvant treatment for early breast cancer. The Danish Breast Cancer Group Radiotherapy (DBCG RT) Committee has completed a randomized multicenter trial to provide evidence in the implementation of SDM for Danish breast cancer patients. A generic, in-consult patient decision aid template (PtDA) has previously been developed. The PtDA was adjusted to support SDM on adjuvant whole-breast irradiation. The primary objective was to investigate whether the adjusted in- consult PtDA affects patient-reported SDM on adjuvant radiotherapy. NCT04177628. Materials and Methods Doctors at four radiotherapy departments were randomized to either continue usual practice or receive a 30-minutes introduction to SDM and use an in-consult PtDA. Eligible patients were candidates for adjuvant whole-breast irradiation after breast-conserving surgery. The primary endpoint was patient-reported SDM in clinical encounters measured by the SDM-Q-9 questionnaire. Other endpoints were patient-reported SDM measured by the SDMP4 questionnaire and the CollaboRATE questionnaire, doctor-reported SDM, patient-reported decisional conflict, decision regret after 6 months, fear of cancer recurrence, patient knowledge about RT, and health-related quality of life. Inclusion of 662 patients were required to ensure a statistical power of 80 % and to account for 10 % dropout. Results The inclusion ended on the 31st of December 2022. Of the 678 included patients, 633 responded to SDM-Q-9. A Generalized Estimating Equation (GEE) population-averaged model with the departments as clusters were performed. For the SDM-Q-9 questionnaire (range 0-100), the PtDA cohort reported significantly more SDM compared to the control cohort with a β 9.49 (95% CI 8.92-10.06, p<0.0001). The SDM-Q-9 average in the control cohort (intercept) was 59.72 (95% CI 54.24-65.21, p<0.0001). For the SDMP4 questionnaire (range 0-4), the PtDA cohort reported more SDM with a β 0.48 (95% CI 0.33-0.63, p<0.0001), intercept at 1.65 (95% CI 1.14-2.16, p<0.0001). For the CollaboRATE questionnaire (range 0- 9), the PtDA cohort reported more SDM with a β 0.62 (95% CI 0.38-0.86, p<0.0001), intercept at 6.70 (95% CI 5.90-7.43, p<0.0001). In the PtDA cohort, 33% of the patients reported the maximum score for all three questions in the CollaboRATE questionnaire compared to only 17% in the control cohort. Conclusion In-consult use of a PtDA increases patient-reported SDM. The present trial provides evidence on the impact of an in-consult PtDA and may thus pave the way for future implementation of SDM in oncology and beyond. The adjusted PtDA about adjuvant whole-breast radiotherapy decision making may be recommended as standard care. OC-0760 A randomized trial of concurrent versus sequential Tamoxifen with radiotherapy for breast cancer A. Budrukkar 1 , A. Munshi 1 , N. Purandare 2 , S. Puri 1 , S. Lewis 1 , R. Krishnamurthy 1 , R. Jalali 1 , T. Wadasadawala 1 , V. Parmar 3 , N. Nair 3 , S. Gupta 4 , R. Upreti 5 , R. Pathak 1 , V. Rangarajan 2 , R. Sarin 1 , R. Badwe 6 1 Tata Memorial Hospital, Department of Radiation Oncology, Mumbai, India; 2 Tata Memorial Hospital, Department of Nuclear Medicine, Mumbai, India; 3 Tata Memorial Hospital, Department of Surgical Oncology, Mumbai, India; 4 Tata Memorial Hospital, Department of Medical Oncology, Mumbai, India; 5 Tata Memorial Hospital, Department of Medical Physics, Mumbai, India; 6 Tata Memorial Hospital, Department of Surgical Oncology, Mumbai, India Purpose or Objective Tamoxifen and radiotherapy both are known to cause pulmonary fibrosis mediated by TGF- β . This phase 3 randomized trial was done to compare lung toxicity and oncological outcomes of concurrent vs sequential Tamoxifen with radiotherapy in adjuvant treatment of breast cancer (NCT00896155). Materials and Methods Women with large operable breast cancer (pT/cT >5cm) and estrogen receptor and/or progesterone receptor positive status who were planned for hormonal therapy with tamoxifen were randomly assigned after breast conservative surgery (BCS) or modified radical mastectomy (MRM) to receive either concurrent or sequential Tamoxifen with radiotherapy. Stratification was done on the basis of BCS versus MRM and Central Lung Distance (CLD) > 2 cm. Radiation was given to chest wall / whole breast and supraclavicular region with 6MV X rays or telecobalt to a dose of 50Gy/25#/5weeks along with a boost of 15Gy/6#/1week to the tumor bed in BCS. Tamoxifen was administered once daily to a dose of 20 mg for 5 years. The primary end point of the study was development of lung fibrosis evaluated using high resolution computed tomography