Head and neck cancer prevention

Abstract

Head and neck cancer (HNC) represents a broad spectrum of diseases that involves the nasal and oropharyngeal cavities, the paranasal sinuses, the major and minor salivary glands, the larynx, and the lymphatic tissues of the neck. The worldwide yearly incidence exceeds over half a million cases. Tobacco (smoking and smokeless) and alcohol use are the principal risk factors; however, a substantial and increasing proportion of head and neck tumors cannot be attributed to these. Recent evidence has shown that the incidence of oropharyngeal cancer among women and younger patients continues to grow, and it is not related to alcohol or tobacco use but to human papillomavirus infection. Substantial advances in treatment regimens made over the last two decades have not improved the 5-year mortality rate that remains around 60 %. Prevention represents the best opportunity to improve oncologic results, and it consists of three levels of intervention: primary prevention (considered the best) aims to avoid exposure to established risk factors; secondary prevention consists of early diagnosis; and tertiary prevention involves active management of patients already treated for HNC. In this chapter, we review the natural history of oral cavity and laryngeal cancer as well as the known mechanisms of carcinogenesis. Precancer and risk markers for cancer are discussed as they relate to prevention in all its forms (primary, secondary, and tertiary). Chemoprevention is the use of natural or synthetic chemicals to reverse, suppress, or prevent the conversion of a premalignant lesion to a true neoplasm. It spans all three forms of prevention, and it can aim at both local and locoregional disease control. All of the major important chemoprevention clinical trials reported on in the scientific literature are presented and discussed critically, and their impact on clinical practice is presented. Attention is given to new directions in the field and how HNC prevention may progress through the search for new, sensitive, and specific biomarkers as well as an improved understanding of the biomolecular mechanisms of tumor invasion, metastasis, and the newly acquired data from the Human Genome Project. Improvement in HNC prevention requires a multidisciplinary approach to face complex processes and multiple factors that may act concurrently in the etiology of disease. Future challenges remain in the correct interpretation of new findings and their wise and scientific application. Only then will we be able to impact the field of HNC, transforming prevention into the only form of cure.