Evaluation of mid-treatment

Background: Oral mucositis is a debilitating yet potentially modifiable toxicity frequently encountered in patients receiving head and neck radiotherapy. This study aimed to evaluate mid-treatment functional changes in the oral cavity using fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) and correlate these early imaging findings with moderate-severe mucositis at the completion of radiotherapy in patients with mucosal head and neck squamous cell carcinoma (HNSCC). Methods: A total of 54 patients with newly diagnosed mucosal HNSCC without distant metastases from two prospective imaging biomarker studies received FDG-PET/CT imaging at baseline and mid-treatment (week 3). The oral cavity was volumetrically segmented at baseline on the CT component of the CT-PET, with this volume transferred to mid-treatment imaging. The median standardised uptake value (SUV Results: Forty-six patients (82.1%) developed moderate-severe [Common Terminology Criteria for Adverse Events (CTCAE) grade ≥2] mucositis at completion of treatment. The average oral cavity SUV Conclusions: Our study demonstrated that functional changes in the oral cavity as seen on mid-treatment FDG-PET/CT correlate with development of moderate-severe mucositis at completion of radiotherapy. Integration of this imaging data with clinical variables may enhance mucositis risk prediction, with potential application in the individualisation of head and neck radiotherapy.