We initially conducted a prospective study evaluating diagnostic interest of FDG PET-CT for head and neck squamous cell carcinomas subclinical recurrence. Our results showed FDG PET-CT high performance in systematic monitoring, especially for the diagnosis of recurrence in about one third of clinically asymptomatic patients 1 year after the end of treatment. Secondly, we studied the benefits of early treatment evaluation by FDG PET-CT after 2 cycles of neoadjuvant chemotherapy by DCF (docetaxel, cysplatin, 5-fluorouracil) before chemoradiotherapy in a cohort of patients with locally advanced cancer (stage III-IVA). Our results showed a statistically significant correlation between metabolic tumor response and recurrence-free survival, suggesting the interest of an interim PETscan to early target patients refractory to treatment. Then, we prospectively analyzed the prognostic impact of FDG PET-CT performed at initial staging in order to select earlier this population at risk for recurrence. The results of our two studies proved that the use of volumetric or kinetic parameters of intratumoral FDG uptake was predictive of overall survival, with an independent prognostic value and a higher performance to SUVmax. Thus, this thesis opens new perspectives indications of FDG PET-CT in the management of head and neck squamous cell carcinoma, raises research issues such as the emergence of new tracers to characterize at best the tumor cell and falls within a current commitment to move towards a personalized preventive and predictive medicine.
