RT Journal Article SR Electronic T1 The predictive value of early assessment after one cycle of induction chemotherapy with 18F-FDG-PET/CT and DW-MRI for response to radical chemoradiotherapy in head and neck squamous cell carcinoma JF Journal of Nuclear Medicine JO J Nucl Med FD Society of Nuclear Medicine SP jnumed.116.174433 DO 10.2967/jnumed.116.174433 A1 Wong, Kee Howe A1 Panek, Rafal A1 Welsh, Liam C A1 Mcquaid, Dualta A1 Dunlop, Alex A1 Riddell, Angela A1 Murray, Iain A1 Du, Yong A1 Chua, Sue A1 Koh, Dow-Mu A1 Bhide, Shreerang A1 Nutting, Christopher M A1 Oyen, Wim J. G. A1 Harrington, Kevin J A1 Newbold, Kate L YR 2016 UL http://jnm.snmjournals.org/content/early/2016/07/11/jnumed.116.174433.abstract AB Objectives: To assess the predictive value of early assessment (after one cycle of induction chemotherapy (IC)) with 18F-FDG-PET/CT and DW-MRI for subsequent response to radical chemoradiotherapy in locally advanced head and neck squamous cell carcinoma (HNSCC). Methods: 20 patients with stage III-IVa HNSCC prospectively underwent 18F-FDG-PET/CT and diffusion-weighted MRI (DW-MRI) before and 2 weeks following each cycle of IC (1st cycle - IC1, 2nd cycle - IC2). Response was assessed 3 months after completion of chemoradiotherapy with clinical examination, MRI and 18F-FDG-PET/CT. Patients with persistent disease were classed as non-responders. Changes in functional and molecular imaging (FMI) parameters following IC1 were compared between responders and non-responders with Mann-Whitney U test. The significance threshold was set at P<0.05. Results: Responders showed a significantly greater reduction in metabolic tumour volume (MTV)(P = 0.03) and total lesion glycolysis (TLG)(P = 0.04) following IC1 than non-responders. Responders also showed a tendency towards a larger, but statistically non-significant increase in apparent diffusion coefficient following IC1. There was no significant difference in the changes from baseline between the IC1 and IC2 for all FMI parameters indicating that most biological response to IC measured by 18F-FDG-PET/CT and DW-MRI was observed early after the first cycle of IC. Conclusion: Our preliminary data indicate that the 18F-FDG-PET/CT-derived MTV or TLG, acquired after IC1 are early predictive biomarkers for ultimate response to subsequent chemoradiotherapy. This enables identification of patients at risk of treatment failure at an early time-point, permitting treatment individualisation and consideration of alternative strategies such as radiotherapy dose-escalation or surgery.