ESTRO 2024 - Abstract Book

S1278

Clinical - Head & neck

ESTRO 2024

For larger targets planning can be challenging, especially if adjacent to radiosensitive OARs. To treat larger nodal levels with hypofractionated dose a two dose level approach as adopted in the SHINE study(2) is required.

Keywords: SBRT, H&N, planning

References:

Khan, L., Tjong, M., Raziee, H. et al. Role of stereotactic body radiotherapy for symptom control in head and neck cancer patients. Support Care Cancer 23, 1099 – 1103 (2015).

Lee J, Nguyen NT, Wright J, Yeung KD, Sagar S, Kim DH, Ostapiak O, Doerwald-Munoz L, Whelan T. A phase 2 study of stereotactic body radiation therapy for squamous cell carcinoma of the head and neck (SHINE): a single arm clinical trial protocol. BMC Cancer. 2023 Apr 26;23(1):379.

1293

Digital Poster

Immunotherapy-related hypothyroidism on head and neck cancer: impact of RT dose to the thyroid gland

Lucia Angelini 1 , Carlotta Becherini 1 , Luca Burchini 1 , Giulio Frosini 1 , Beatrice Bettazzi 1 , Doruntina Cela 1 , Luisa Caprara 1 , Ilaria Bonaparte 1 , Anna Peruzzi 1 , Chiara Arilli 2 , Gabriele Simontacchi 1 , Emanuela Olmetto 1 , Monica Mangoni 1 , Viola Salvestrini 1 , Isacco Desideri 1 , Pierluigi Bonomo 1 , Lorenzo Livi 1 1 Radiation Oncology, Azienda Ospedaliera Universitaria Careggi, Università di Firenze, Florence, Italy. 2 Medical Physics Unit, AOU Careggi, Florence, Italy

Purpose/Objective:

Radiotherapy (RT) and immunotherapy (IT) are part of the therapeutic armamentarium for head and neck squamous cell carcinoma (HNSCC) in different moments of the disease trajectory. Hypothyroidism is a prevalent side effect associated with both RT and IT. Nevertheless, there is a lack of identified dosimetric or clinical factors that can predict thyroid function outcomes, and there is no existing literature documenting any potential interplay between RT and IT in causing thyroid damage. This study aims to investigate how RT influences the likelihood of hypothyroidism in HNSCC patients undergoing IT treatment.

Material/Methods:

We conducted a retrospective analysis of patients diagnosed with HNSCC, categorizing them into two groups: those who received both RT and IT (referred to as the RT-IT group) and those who received IT alone or palliative RT with a total dose less than 50 Gy (referred to as the IT group). We collected demographic and clinical data for all patients, as well as specific RT information such as the total dose, number of fractions, RT intent, and dosimetric data, which included parameters like the mean thyroid dose (tDmean), total thyroid volume (tVtot), the volume of thyroid exposed to 50 Gy (tV50), and the volume of thyroid exposed to 60 Gy (tV60). Additionally, we documented the