151751-Najiba-Chargi

13 Introduction Heavy use of tobacco causes most head and neck cancers, and heavy use of alcohol syner - gistically increases the risk caused by tobacco use. The incidence of head and neck cancers caused by these risk factors is globally slowly declining, in part because of decreased use of tobacco. 5 The second most common cause of head and neck cancer is infection with the sexually transmitted human papillomavirus (HPV); commonly high-risk HPV type 16. 6 Over the past decade, there is increasing incidence of HPV-related head and neck cancers. 7 HPV leads to expression of E6 and E7 oncoproteins that inactivate the tumor-suppressor proteins p53 and the retinoblastoma protein (pRb), respectively, which leads to the malignant behavior of HPV-related tumors. 8 HPV-related head and neck cancers are typically located in the oro - pharynx. Patients with HPV-related head and neck cancers have unique risk factor profiles, better prognosis and have different epidemiology. 9 HPV-related head and neck cancers are more frequently seen in white men under age of 50 who usually do not smoke or use alcohol. 10 HNSCC is staged according to the 8 th edition of the American Joint Committee on Cancer (AJCC). 11 Staging is based on the size or extent of the primary tumor, involvement of lymph nodes and distant metastases, which are the T, N and M stage respectively. Combinations of these T, N and M stages are grouped in four disease stages. The TNM stage is a strong prog - nostic factor for disease outcome; patients with higher stages of disease are more likely to experience poorer survival outcomes. Generally, early stage head and neck cancer (stage I and II) includes smaller tumors without lymph node involvement and advanced stage head and neck cancers (stage III and IV) are characterized by more extensive local tumors with frequently invasion of surrounding structures, tumor involved lymph nodes and/or distant metastatic spread. 11 CURATIVE TREATMENT OPTIONS FOR PATIENTS WITH HEAD AND NECK CANCER Early-stage head and neck cancer (stage I and II) can generally be treated with primary surgery or radiotherapy. For oral cavity cancer, surgical resection of the primary tumor with elective neck dissection or sentinel node biopsy is preferred. This is followed by adjuvant radiotherapy or chemoradiotherapy depending on the presence of adverse histopathological features. At other sites, surgery is usually only performed for small and endoscopic accessible early-stage head and neck cancer. The 5-years overall survival for early-stage head and neck cancer ranges from 60 to 98% and varies between tumor sites. More than 60% percent of the patients pres - ent at diagnosis with locally advanced stage head and neck cancer (stage III and IV). 4 Treating locally advanced stage HNSCC requires evaluation by a multi-specialty team and multimodal treatment since the choice of treatment is dependent on the stage of the disease, anatomical site, surgical accessibility and preference of the patient (i.e., preserving function at the expense of survival). Multimodal treatment compromises (1) primary surgery with or without postop - erative radiotherapy or chemoradiotherapy or (2) primary concomitant chemoradiotherapy or radiotherapy in combination with cetuximab (bioradiotherapy), with salvage surgery in reserve for residual or recurrent disease. In patients with locally advanced oral cavity cancer and hypopharyngeal or laryngeal cancer with cartilage invasion, extralaryngeal extension or an afunctional larynx, primary surgery is the treatment of choice. Salvage surgery can also be 1