ESTRO 2024 - Abstract Book

S691

Clinical - Breast

ESTRO 2024

Further long-term follow-up is warranted to explore the role of CPAP as a method to reduce the risk of normal organ toxicity.

Keywords: breast cancer, respiratory motion management

References:

1) Jacobson G, Lawrence YR, Appel S, et al. Benefits of Continuous Positive Airway Pressure (CPAP) During Radiation Therapy: A Prospective Trial. Int J Radiat Oncol Biol Phys. 2021;110(5):1466-1472. doi:10.1016/j.ijrobp.2021.03.044

2888

Digital Poster

Safety of trastuzumab deruxtecan and radiation therapy in HER2-positive breast cancer patients

Luca Visani 1 , Ivica Ratosa 2 , Domen Ribnikar 3 , Carlotta Becherini 1 , Niccolò Bertini 1 , Ilaria Bonaparte 1 , Dimitar Stefanovski 3 , Nika Dobnikar 2 , Isacco Desideri 1 , Emanuela Olmetto 1 , Monica Mangoni 1 , Vanessa Di Cataldo 1 , Anna Peruzzi 1 , Chiara Mattioli 1 , Doruntina Cela 1 , Marianna Valzano 1 , Viola Salvestrini 1 , Erika Scoccimarro 1 , Lorenzo Livi 1 , Icro Meattini 1 1 Azienda Ospedaliero-Universitaria Careggi, Radiation Oncology Unit, Florence, Italy. 2 Institute of Oncology, Division of Radiotherapy, Ljubljana, Slovenia. 3 Institute of Oncology, Division of Medical Oncology, Ljubljana, Slovenia

Purpose/Objective:

Trastuzumab deruxtecan (T-DXd) currently represents the standard of care for the treatment of patients with metastatic HER2-positive (HER2+) breast cancer (BC) after disease progression to first line containing taxanes and trastuzumab, based on the results of the DESTINY-Breast03 trial showing improved efficacy in respect to trastuzumab emtamsine (T-DM1). Radiation therapy (RT) is frequently required in the metastatic setting, either with palliative or ablative intent in case of oligometastatic or oligoprogressive disease. The aim of our study is to evaluate the safety of the use of T-DXd and concomitant RT in a consecutive series of HER2+ BC patients.

Material/Methods:

We retrospectively evaluated patients diagnosed with metastatic HER2+ BC, treated at two leading European institutions (University of Florence, Italy and Institute of Oncology, Ljubljana) who started treatment with T-DXd between May 2021 and August 2023, receiving RT or not. We collected clinical data related to the diagnosis of metastatic disease, treatment with T-DXd, acute and late toxicities, survival data and biological characteristics of both primary tumor and metastases. Primary outcome of the study was the association between RT and any adverse events (AEs) > grade (G)2.