Basic consideration of research strategies for head and neck cancer.

Head and neck cancer (HNC) consists of a group of malignancies affecting closely related anatomical regions of the upper aerodigestive tract (UADT), including the oral cavity, salivary glands, upper and lower jaw bones and facial skin; the nasal cavity, paranasal sinuses, pharynx, larynx and thyroid gland (although the latter is often excluded and considered as part of endocrine neoplasms). Of these, 90% of HNCs are histologically squamous cell carcinomas originating from the mucosal lining. These malignancies are strongly associated with certain environmental and life-style risk factors, principally tobacco in both smoked and smokeless forms, excessive alcohol consumption, diets poor in antioxidants and essential micronutrients, UV light, chemicals used in certain workplaces, and viruses, principally certain strains of human papillomavirus (HPV) and Epstein-Barr virus (EBV). These cancers are frequently aggressive in their biological behaviour with local invasion and metastasis to lymph nodes in the neck. Since most patients are already at late stages of disease at the time of diagnosis, the desirable practice of early diagnosis (first sign of the malignant lesion at an initial stage) and early treatment, a critical priority to save lives and retain quality of life, is difficult to implement. Thus, primary prevention has been set as a key goal. This article aims to reinforce the basic knowledge of aetiology, key risk factors related to the development of head and neck cancer, basic features of clinical appearance of this group of cancers, and strategies for prevention and early detection.We also suggest basic research strategies on the basis of current knowledge, which should ultimately lead to the improvement of clinical management.