ABSTRACT
INTRODUCTION Head and Neck Cancer: Epidemiology, Classification, and Treatment The number of new head and neck cancer cases in the United States in 2005 is estimated at more than 40,000. This represents about 3% of the estimated total new cancer cases for 2005 (1). The oral cavity, pharynx and larynx are the most frequent primary sites (94%). Head and neck cancer is more frequent in men after the age of 40, with a peak incidence in the 5th and 6th decades. The vast majority of cases are related to prolonged exposure to environmental factors, mainly tobacco and alcohol. Association with pulmonary, hepatic, vascular or nutritional disorders related to chronic tobacco or alcohol exposure is not unusual; further, these disorders are a potential source for neurological manifestations in the patient with head and neck cancer.
