ESTRO 2025 - Abstract Book

S1039

Clinical – Head & neck

ESTRO 2025

Purpose/Objective: The aim of the current study was to investigate rates and patterns of locoregional recurrence in a series of patients with locally advanced squamous cell carcinoma (SCC) of the oropharynx, hypopharynx, and larynx treated with definitive radiotherapy in combination or not to systemic therapy. Material/Methods: We retrospectively reviewed 214 consecutive patients with primary SCC who was planned to receive definitive radiotherapy between 2016 and 2023. A series of patients with following characteristics was selected: histology confirmed SCC, locally advanced stage, completed RT, sufficient follow up data. Exclusion criteria were as follows: distant metastases at the time of RT, non-SCC histology, oral cavity or lateralized tumors, palliative RT, no follow up data. Of the 214 patients, 177 patients fulfilled the inclusion criteria. The high-dose tumor areas received a median dose 70,2Gy (range 56-72Gy) and the low-dose areas of the neck received a median does if 57,6Gy (range 50,4-57,6Gy). The treatment was planned using IMRT or VMAT for all patients. Patterns of relapse are defined according Mohamed et al. as follows: Group 1:relapse in the central high-dose volume - a.primary, b.involved nodes; Group 2:relapse in the peripheral high-dose volume, - a. primary, b.involved nodes; Group 3:relapse in the central elective volume; Group 4:relapse in the peripheral elective volume; Group 5:relapse outside the irradiated volume in the head and neck region.

Results: