ESTRO 2024 - Abstract Book

S479

Clinical - Breast

ESTRO 2024

Results:

With a median follow-up of 12 years, 95% CI [10-14], 19 patients (76%) were in remission, 1 patient had a controlled axillary lymph node relapse (4%)and 5 patients (20%) died due to metastatic progression within a median of 5 years after treatment (min: 1, max: 9). Nine patients (36%) had a complete histological response (pCR). The highest percentage of pCR was in the group of patients treated in the 4th stage (28.5 Gy in 4 fractions). Overall survival at 14 years was 71%, 95% CI [53%-94%]. Two patients developed chronic radiation toxicity during follow-up with a fibrosis (8%), of which one was in the 4th stage and one in the 5th stage (31.5 Gy). Three patients (12%) had a change of prosthesis after treatment which for one patient was 24 months after the end of support.

Conclusion:

The updated results of the CYBERNEO trial with 14 years of follow-up confirm the satisfactory results in terms of local control with an excellent long-term safety profile.

Keywords: SBRT, breast cancer, neoadjuvant

470

Digital Poster

Varying interpretations of IMN delineation guideline impact heart dose in breast cancer radiotherapy

Emma S Buhl 1,2 , Geert Wortel 3 , Rita Simões 3 , Astrid Scholten 4 , Birgitte V Offersen 5,2,6 , Stine Korreman 1,2,6 , Tomas Janssen 4 1 Aarhus University Hospital, Danish Center for Particle Therapy, Aarhus, Denmark. 2 Aarhus University, Department of Clinical medicine, Aarhus, Denmark. 3 The Netherlands Cancer Institute – Antoni van Leeuwenhoek, Department of Radiation Oncology, Amsterdam, Netherlands. 4 Netherlands Cancer Institute – Antoni van Leeuwenhoek, Department of Radiotherapy, Amsterdam, Netherlands. 5 Aarhus University Hospital, Department of Clinical Medicine, Aarhus, Denmark. 6 Aarhus University Hospital, Department of Oncology, Aarhus, Denmark

Purpose/Objective:

ESTRO delineation guidelines [1] for breast cancer patients are widely used in European countries. However, guidelines can be interpreted differently which may affect the treatment plan. In this study, we investigated the dosimetric impact on mean heart dose (MHD), when the left-sided internal mammary lymph node chain (IMN) clinical target volume was delineated with two different interpretations of the same ESTRO guideline.

Material/Methods: