Geometric analysis of loco-regional recurrences in relation to pre-treatment hypoxia in patients with head and neck cancer

AbstractIntroduction: A previous pattern-of-failure study has suggested that up to 50% of the loco-regional failures (LRF) in head and neck squamous cell carcinoma (HNSCC) occur outside the initial hypoxic volume determined by [18F]-fluoromisonidazole-PET ([18F]-FMISO-PET). The aim of the present analysis was to correlate spatial patterns of failure with respect to the pretherapeutic dynamic [18F]-FMISO-PET/CT in HNSCC after radiochemotherapy (RCT).Material and methods: Within a running phase 2 trial using [18F]-FMISO-PET imaging prior to RCT in HNSCC patients (n = 54), we have observed so far 11 LRF with a minimum follow-up of 12 months. For nine patients, LRF imaging (CT or [18F]-FDG-PET/CT) for pattern-of-failure analysis was available. Analysis included the static 4-h hypoxic subvolume (VH) as well as a M-parameter volume (VM), which is derived from modeling of dynamic PET. Deformable image registration of the CT scan with the recurrent tumor to the pre-treatment [18F]-FMISO-PET/CT and the planning CT...