PT - JOURNAL ARTICLE AU - Kee Howe Wong AU - Rafal Panek AU - Liam C Welsh AU - Dualta Mcquaid AU - Alex Dunlop AU - Angela Riddell AU - Iain Murray AU - Yong Du AU - Sue Chua AU - Dow-Mu Koh AU - Shreerang Bhide AU - Christopher M Nutting AU - Wim J. G. Oyen AU - Kevin J Harrington AU - Kate L Newbold TI - The predictive value of early assessment after one cycle of induction chemotherapy with <sup>18</sup>F-FDG-PET/CT and DW-MRI for response to radical chemoradiotherapy in head and neck squamous cell carcinoma AID - 10.2967/jnumed.116.174433 DP - 2016 Jul 01 TA - Journal of Nuclear Medicine PG - jnumed.116.174433 4099 - http://jnm.snmjournals.org/content/early/2016/07/11/jnumed.116.174433.short 4100 - http://jnm.snmjournals.org/content/early/2016/07/11/jnumed.116.174433.full 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&lt;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.