ESTRO 2025 - Abstract Book

S1044

Clinical – Head & neck

ESTRO 2025

2790

Digital Poster Fighting xerostomia in head and neck patients treated with radiotherapy: the challenging strategy of the parotid gland stem cell sparing. Luca Bergamaschi 1 , Maria Giulia Vincini 1 , Giulia Marvaso 1,2 , Ferrari Annamaria 1 , Volpe Stefania 1 , Federica Cattani 3 , Rosa Luraschi 3 , Sabrina Vigorito 3 , Michela Onza 1 , Federico Gagliardi 1 , Karl Amin 1 , Maria Cossu Rocca 4 , Ansarin Mohssen 5 , Barbara Alicja Jereczek-Fossa 1,2 , Daniela Alterio 1 1 Division of Radiation Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy. 2 Department of Oncology and Hemato-Oncology, University of Milan, Milan, Italy. 3 Unit of Medical Physics, IEO European Institute of Oncology IRCCS, Milan, Italy. 4 Department of Medical Oncology, IEO European Institute of Oncology IRCCS, Milan, Italy. 5 Department of Otolaryngology and Head and Neck Surgery, IEO European Institute of Oncology IRCCS, Milan, Italy Purpose/Objective: Despite the implementation of modern technologies, xerostomia is still one of chronic side effects most impacting the QoL of head and neck patients (pts) treated with RT. The parotid gland has a pivotal role in salivary production and it encloses a stem cells-rich region (SCRR). The present work aims to present preliminary results on eventual association between the dose received from the SCRRs and the degree of long-term xerostomia in a cohort of oropharyngeal cancer pts. Material/Methods: Pts treated with RT at our Department from 2012 to 2019 were retrospectively considered for study inclusion, in case of: (i) confirmed primary tumor of the oropharynx; (ii) RT with curative intent with VMAT technique, either combined or not with systemic treatment; (iii) physician-rated grade 2 (G2) or grade 0 (G0) chronic xerostomia one year after RT, according to the CTCAE v.4. The RT treatment plan was optimized following the standard procedure of our center, ensuring the CTV coverage, and striving to comply with the OARs constraints (for the parotid gland: average dose < 26 Gy – volume receiving 30 Gy < 50%). The SCRRs were retrospectively contoured by a single radiation oncologist (LB), identifying a specific volume at the intersection of the parotid gland, mandible and masseter muscle. The median dose received by parotid glands, SCRRs, and the oral cavity was retrospectively collected. For the preliminary analysis only pts with G2 and G0 xerostomia were considered and analyzed. Results: Sixteen pts (over 116 eligible pts) were included in the current preliminary analysis (9 with xerostomia G2 and 7 with xerostomia G0).