ESTRO 2025 - Abstract Book

S969

Clinical – Head & neck

ESTRO 2025

Analysis of the data demonstrates positive correlation between the number of QS treatments delivered (maximum 3 courses) and the overall survival, as measured from the decision to treat date (DTTD), in patients receiving treatment to the primary tumour and to both the primary tumour and metastatic cervical nodes. Furthermore, overall survival is inversely correlated with PTV volume. CTCAE v toxicity scores were consistently ≤ 2 and PTV volume did not have an impact on toxicity. Of note, there was no correlation between tumour stage and survival, as well as no correlation between patient performance status or CCI and survival. Conclusion: The authors have shown that quad shot radiotherapy is a deliverable palliative treatment for advanced HNSCC, which is universally well tolerated 2 , and where overall survival correlates with the number of courses delivered. The inverse correlation with the PTV volume is to be expected. This treatment has the advantage of minimising travel for patients in rural areas and should be considered when concerned about potential toxicity risks, supporting its use in effective palliative RT in HNSCC. References: 1. Corry J et al. The 'QUAD SHOT' - a phase II study of palliative radiotherapy for incurable head and neck cancer. Radiotherapy and Oncology [online]. 2005; 77; 137-142 [Accessed 6/6/24] 2. National Cancer Institute. Common Terminology Criteria for Adverse Events (CTCAE). [online]. USA; 2017 [6/624] Available from:https://ctep.cancer.gov/protocoldevelopment/electronic_applications/docs/CTCAE_v5_Quick_Reference_8.5x11 .pdf 3. Katano A et al. Survival Following Palliative Radiotherapy for Head and Neck Squamous Cell Carcinoma: Examining Treatment Indications in Elderly Patients. Cancer Diagnosis & Prognosis [online]. 2024; 4(1): 46-50. [Accessed 17/11/24]. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC10758838/ Keywords: Quad shot Mini-Oral Patterns of lymphatic spread in laryngeal squamous cell carcinoma and personalization of the elective clinical target volume Esmée L Looman 1,2 , Tineke W H van Zon-Meijer 3 , Yoel Pérez Haas 1,2 , Roman Ludwig 1,2 , Johannes A Langendijk 3 , Matthias Guckenberger 1,2 , Panagiotis Balermpas 1,2 , Jan Unkelbach 1,2 1 Radiation Oncology, University Hospital Zurich, Zurich, Switzerland. 2 Faculty of Medicine, University of Zurich, Zurich, Switzerland. 3 Radiation Oncology, University Medical Center Groningen, Groningen, Netherlands Purpose/Objective: Aiming for personalization of elective clinical target volumes (CTV), we are reporting on regional lymphatic spread patterns and risk of lymph node metastases in laryngeal squamous cell carcinoma (SCC), considering not only subsite, T-stage, and lateralization of the primary tumor, but also involvement of adjacent lymph node levels (LNLs). Material/Methods: LNL involvement in 1005 patients with laryngeal SCC treated at University Hospital Zurich between 2013-2021 and UMCG Groningen between 2006-2023 was analyzed. LNL involvement was assessed based on imaging and, if available, pathology. The dataset will be publicly available and patterns of LNL involvement can be visualized on https://lyprox.org/. 1303

Results: Patients with glottic (N=633), supraglottic (N=339) and subglottic (N=15) SCC were included. Overall prevalence of