18F-FDG-PET/CT-guided radiotherapy of cervical lymph nodes in head and neck squamous cell carcinoma

Abstract

The use of positron emission tomography with fluor-18-fluorodeoxyglucose (FDG-PET) in clinical practice for patients with head and neck squamous cell carcinoma (HNSCC) has expanded rapidly, with implications for diagnostic staging, radiotherapy planning, adaptive radiotherapy, and post-therapy evaluation. The implementation of FDG-PET/CT in radiation treatment planning not only has consequences for target volume definition and dose prescription but is also associated with an increased overall survival in patients with HNSCC. FDG-PET/CT-guided gradient dose prescription provides a window of opportunity for treatment de-intensification of the neck in order to decrease treatment-related toxicity without compromising oncological outcome. Further, interim FDG-PET/CT during radiotherapy can be useful to assess metabolic tumor response and enables opportunities for adaptive treatment strategies. The goals are to increase treatment effectivity in poor responders and reduce unnecessary toxicity in patients with good early tumor response. Further prospective trials investigating adaptive radiotherapy based on interim PET-evaluation are needed, especially regarding human papilloma virus-negative HNSCC and patients treated with primary radiotherapy.