ESTRO 2025 - Abstract Book

S3131

Physics - Inter-fraction motion management and offline adaptive radiotherapy

ESTRO 2025

2296

Digital Poster Adoption of Traffic Light Protocol in Head and Neck Radiotherapy - a before and after comparison Jino Victor Wilson 1 , Rajalakshmi Radhakrishnan 2 , Rajendra Benny K 1 , Manu Mathew 1 , Rajesh I 1 , Swathi Bapani 1 , Jerome Sunny 1 , Abraham Joel 1 , Hannah Mary Thomas 1 , Balu Krishna S 1 , Simon Pavamani 1 1 Radiation Oncology, Christian Medical College, Vellore, India. 2 Medical Oncology, Madras Medical College, Chennai, India Purpose/Objective: Head and neck cancers (HNC) treated using Volumetric Modulated Arc Therapy (VMAT) require precise setup and planning to target their tumour effectively[1]. Variations in patient setup can disrupt their radiation therapy (RT) necessitating replanning. However, determining which patient requires replanning and when is often challenging. Decision support systems employed using a traffic light protocol (TLP) [2,3] tries to address this issue by providing a structured approach to monitor and manage the treatment variations. In this study we report the impact of the introduction of TLP on the management of HNC in a large tertiary care hospital.

Material/Methods:

The study included a comparative before-and-after with pre-TLP being retrospective patients treated between 2018 2020 and the post-TLP cohort including patients prospectively recruited in 2021. Inclusion criteria were biopsy - proven head and neck carcinomas, planned for definitive or adjuvant radiation therapy with or without concurrent chemotherapy and treated with VMAT. TLP protocol implemented in our institution is shown in Figure 1. We compared rates of replanning, factors affecting replanning and treatment continuity between the cohorts. The effectiveness of TLP was evaluated on the number of treatment break days during RT. Results: 591 and 109 patients were included in the pre-TLP and post-TLP cohorts, respectively. In the pre-TLP cohort 120/591 patients (20.9%) underwent replanning, primarily due to weight loss and body contour changes (51%) and radiation induced toxicities (11%). The fifth week of treatment saw the highest frequency of replanning, with 62.5% (n=75) experiencing breaks, averaging 9.08 days per patient. The average treatment break due to body contour changes and tumour progression was 7.1 days. In contrast in the post-TLP cohort, 24/109 patients (21.4%) underwent re-planning with the most common reason being body contour change (71%). Replanning was more common in the fourth week, 58.3% (n=14) experienced breaks, averaging 5.7 days per patient. The TLP identified 89.4% of body contour changes, 100% of tumour