Participants and data sources
Eligible consecutive patients were identified from a regional head and neck cancer database (SOMERSET), who had a histological diagnosis of locally advanced (AJCC 8 T3 or T4) laryngeal squamous cell carcinoma (ICD-10 C32.9) and underwent definitive either radiotherapy or chemoradiotherapy with curative intent between 2008 and 2018 at a tertiary head and neck centre. Patients received radiotherapy at a dose of 65-70Gy over 30-35 fractions with or without concurrent cisplatin chemotherapy delivered at either 3- or 4-week intervals at a dose of 100mg/m2. All patients were discussed in the regional multidisciplinary team meeting before commencement of treatment. Demographic, clinical and radiological characteristics (cartilage involvement, pre-epiglottic extension) were extracted from the electronic medical records.