Distant metastases in head and neck carcinoma:Identification of prognostic groups with MR imaging

Purpose: To evaluate retrospectively the prognostic significance of lymph node parameters assessed on pretreatment magnetic resonance (MR) images for development of distant metastases in patients with head and neck squamous cell carcinomas. Materials and methods: Pretreatment MR images of 311 patients were retrospectively reviewed for the presence of lymph nodes at specific neck node levels as well as the size and the presence of a number of lymph node characteristics including extranodal spread, central necrosis and number and volume of ipsi- and contralateral nodes. Of these patients, 174 (56%) had MRI-positive nodes (defined as nodes with minimum axial diameter >8 and >4 mm for paratracheal level and retropharyngeal nodes). Results: The 2-year distant-metastasis free survival rate (DMFSR) for patients without MRI-positive nodes was 94% compared to 75% for those patients with MRI-positive nodes. In patients with MRI-positive nodes, results of multivariate analysis with the Cox regression model yielded statistical significance for presence of extranodal spread (ENS), detected on MRI, as the only independent prognostic factor associated with the 2-year DMFSR (p = 0.002). Based on the analysis, three risk groups regarding the DMFSR could be identified. Low-risk group (DMFSR:94%) consisted of patients without MRI-positive nodes. Intermediate-risk group (DMFSR: 81%) consisted of patients with MRI-positive nodes without ENS. High-risk group (DMFSR:59%) consisted of patients with MRI-positive nodes and ENS as shown on MRI (p 5 cm(3) (larynx: p = 0.03; oral cavity: p = 0.02) to be significant predictors with regard to DMFSR. Conclusion: Especially patients with on MRI demonstrating extranodal spread and with suspicious nodes at lowjugular/posterior triangle (oropharyngeal cancer) or paratracheal level (laryngeal cancer), or with contralateral enlarged nodes (laryngeal and oral cavity cancer) are at high risk for developing distant metastases and this subset of patients might benefit from supplementary imaging screening (CT-chest, PET-scan). (C) 2006 Elsevier Ireland Ltd. All rights reserved

Thermal modelling using discrete vasculature for thermal therapy:A review

Reliable temperature information during clinical hyperthermia and thermal ablation is essential for adequate treatment control, but conventional temperature measurements do not provide 3D temperature information. Treatment planning is a very useful tool to improve treatment quality, and substantial progress has been made over the last decade. Thermal modelling is a very important and challenging aspect of hyperthermia treatment planning. Various thermal models have been developed for this purpose, with varying complexity. Since blood perfusion is such an important factor in thermal redistribution of energy in in vivo tissue, thermal simulations are most accurately performed by modelling discrete vasculature. This review describes the progress in thermal modelling with discrete vasculature for the purpose of hyperthermia treatment planning and thermal ablation. There has been significant progress in thermal modelling with discrete vasculature. Recent developments have made real-time simulations possible, which can provide feedback during treatment for improved therapy. Future clinical application of thermal modelling with discrete vasculature in hyperthermia treatment planning is expected to further improve treatment qualit