ESTRO 2025 - Abstract Book

S1138

Clinical – Head & neck

ESTRO 2025

Conclusion: Although there appeared to be no difference at 3-6 month endoscopy, patients who used the mouthwash from the start of treatment had better weight control and less mucositis.The mouthwash was well tolerated and delayed (C)RT-induced mucositis, allowing for continued treatment of locally advanced head and neck cancer.

Keywords: head and neck cancer, supportive care

4419

Digital Poster influence the interval time between surgery and start of adjuvant radiotherapy for head and neck cancer prognosis Scarlet M Crespo 1 , Laura C Montezuma 1 , Xavi Leon 2 , Katarina Majercakova 1 , Jady V Rojas 1 , Gemma Calvet 1 , Saba Rabi 1 , María M Piedra 1 , Joan C Juliá 1 , Gemma Sancho 1 1 Radiation Oncology, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain. 2 Otorhinolaryngology, Hospital de la Santa Creu i Sant Pau, Barcelona, Spain Purpose/Objective: Adjuvant radiotherapy (ART) in Head and Neck Cancer (HNC) reduces the risk of locoregional failure (LRR) (1). Delaying the initiation of ART >6-8 weeks seems to be associated with LRR (2). Our objective is to evaluate the relationship between delay of RT initiation and locoregional control (LRC). Material/Methods: Retrospective study including 508 patients with HNC undergoing by ART (>50Gy) between 1986-2021. The relationship between LRC and the interval time until the start of RT (RT-T) was analyzed using a recursive partition analysis. Defined two cut-off points in RT-T at 54.5 and 78.5 days. The LRC was the dependent variable. Results: Median RT-T was 7.5 week. 76 patients (15%) started RT the month 1, 294p (58%) month 1 and 2, 107p (21%) month 2 and 3; and 31p (6%) after month 4. Tumor location in the larynx (56.3%), oral cavity (20.5%), oro-hypopharynx (13.2%), nasal area (10%). 68% stage III-IV. The 5y survival free of LRR(LRR-FS) for node 3 (320p 63%) with an interval <54.5 days was 83.1%, for node 4 (133p 26.2%) with an interval 54.5-78.5 days was 76.4%, and for node 2 (55p 10.8%) >78.5 days it was 63.3% (Figure 1) . There were significant differences in LRR-FS depending on the RT-T (Figure 2). Considering the node 3 as the reference category, the node 4 had a 1.44 times higher risk of LRR and the node 2 had a 2.75 times.