Curative radiotherapy is part of the multimodal treatment for locally advanced head and neck cancers. The technical revolution in the field of radiation therapy and medical imaging has made possible a better conformation of the target volumes with irregular shapes with a dose reduction at the radiosensitive organs in the vicinity. Three-dimensional Conformal Radiotherapy (3D-CRT) has been replaced by Intensity Modulated Radiotherapy (IMRT), and more recently the Intensity Modulated Volumetric Arc Therapy (VMAT) technique is being used on an ever-expanding scale as a replacement for the „step and shot” IMRT technique. The benefits of the IMRT/VMAT techniques were mainly consisting of a better conformation for the target volumes with irregular shapes and the reduction of acute and late xerostomia. The results in the tumor control are considered similar to those obtained by the 3D-CRT technique except for nasopharyngeal cancer in which the use of chemo-radiotherapy by the IMRT technique has led to an improved local survival and local and regional control rate. Increasing the incidence of HPV-positive head and neck cancers with a better prognosis and the need to improve quality of life would be an argument in favor of using treatments with a low toxicity profile. By reducing the dose of healthy tissue, the use of modern irradiation techniques opens new horizons for the re-irradiation with high radiation doses of recurrent head and neck tumors.

Diabetes mellitus is often associated with a risk of developing some types of cancer. The association between head and neck cancers and diabetes as well as prognosis and treatment tolerance remains a controversy. Acute toxicities associated with treatment may be amplifi ed by the presence of comorbidities, including hypertension, diabetes and collagen diseases. Another factor implicated in the treatment tolerance is also the limitation by the presence of hyperglycemia of the corticosteroids dose used for the control of pain and edema associated with chemo-irradiation and for the treatment of thrombocytopenia. The purpose of the study was to evaluate the involvement of diabetes mellitus in the toxicities associated with chemo-radiotherapy treatment in multimodal treated patients for advanced local head and neck cancers. For patients with locally advanced non-metastatic head and neck treated with multimodal (chemo-radiotherapy) acute toxicities (radio-dermitis, radio-mucositis, dysphagia) was analyzed comparatively in patients who associate or not cancer with diabetes. It was also compared if the diagnostic of diabetes influenced the intensity of chemotherapy. Identifying the predictive value of diabetes mellitus for the severity of toxicities in multimodal curative treatment for head and neck cancers can lead to limitation of radiation dose to some radiosensitive anatomical structures in the context of the modern IMRT and VMAT irradiation techniques implementation in clinical practice.