Changing trends in the occurrence and subsite distribution of laryngeal cancer in Finland.

Cancer of the larynx represents worldwide approximately 1-2% of all cancers and generally occurs predominantly in males. Based upon many reports, the age-adjusted incidence of laryngeal cancer has been rising in recent years, especially among women. Squamous cell carcinomas arising in the glottic region are the most common of all laryngeal cancers and more prevalent than the supraglottic ones. Subglottic disease is still rare. The Finnish Head and Neck Oncology Group evaluated the present occurrence of laryngeal cancer by site and gender in Finland. The annual age-standardized incidence of laryngeal cancer is 3.2 per 100,000 for men and 0.3 per 100,000 for women. The proportion of females in the five university centers reviewed was 5%. During the 30-year time period from the early 1960s to the 1990s there has been a significant decrease in the laryngeal cancer incidence rates for males, but no change for females. Finland thus seems to be the only Western country with clearly declining occurrence rates in recent decades. In the same time period a clear decrease in the incidence of bronchial cancer has occurred in males and an increase in females. The results also show that in all five university hospital districts glottic cancer became more common (50-68%) in the late 1980s and 1990s, which is opposite to the situation in the 1960s when supraglottic localizations (65%) dominated in Finland.