[Head and neck malignant tumors in Niigata Prefecture. The first report: demographics in 4,053 cases].

In 1986, the Niigata Registration Committee of Head and Neck Malignant Tumors was established by otolaryngologists in Niigata Prefecture to register cases of head and neck malignancies. Between 1986 and 1999, 4,053 cases were registered and we epidemiologically analyzed them. Men accounted for 2,866 (70.7%) and women for 1,187 (29.3%). The mean age and standard deviation of the age at diagnosis were 63.4 and 12.4 in men and 59.5 and 16.0 in women. The larynx was the most common site (1,154 cases) in men, followed by the oral cavity (360 cases), hypopharynx (273 cases), mesopharynx (239 cases), and maxillary sinus (154 cases). The thyroid gland was the most common site (416 cases) in women, followed by the oral cavity (214 cases), nasal cavity and paranasal sinuses (excluding the maxillary sinus) (76 cases), salivary glands (72 cases), and mesopharynx (71 cases). The site with the highest mean age was the lip (71.3 years old) in men and the larynx (68.7 years old) in women. The thyroid gland showed the lowest mean age for both genders (men: 56.7, women: 53.6), and that markedly lowered the female mean age because the thyroid gland accounted for one third of all cases in women. Comparing our data to national statistics, the incidence of oral malignancy was almost half in our data. We concluded that, in Niigata Prefecture, the dental professions treated as many cases of oral malignancy as we did. A high gender ratio (male/female) was seen for the larynx (22.2), hypopharynx (4.3), and mesopharynx (3.4). It was more than 1 and less than 2 for the oral cavity, salivary gland, neck lymphoma, ear, and nasal cavity and paranasal sinuses (excluding the maxillary sinus). The thyroid gland showed the lowest gender ratio (0.3), which was the only female-dominant site. We concluded that many sites of malignant head and neck tumors have a lower gender ratio than previously anticipated.