Squamous cell carcinomas of the head and neck in Norway, 1953-92: an epidemiologic study of a low-risk population.

Trends in incidence, five-year relative survival, and mortality among patients in Norway with squamous cell carcinoma of the oral sites, oro-/hypopharynx, and larynx were studied for the period 1953-92. Throughout the first part of the study period, age-adjusted incidence rates (AAIR) of oral cancer remained stable in both genders. Since the end of the 1960s, AAIRs increased by 13 percent per five-year period in males and 12 percent in females. The figures suggest increased male incidence rates of oral cancer in younger age groups. During the same period, AAIRs of cancers of the oro-/hypopharynx in males increased by 19 percent per five-year period. The AAIRs of laryngeal cancer increased steadily from 1953-92 among both males and females by 17 percent and 21 percent per five-year period, respectively. For all sites, changes in AAIRs for males were greater in rural than in urban areas. No improvement in detection of disease at a localized stage was observed for either gender. There are indications of improvements in the five-year relative survival rates for oral and pharyngeal cancer in both genders. For all sites, relative survival was better in younger than in older patients. Only in the case of pharyngeal cancer in males was an increase in disease-specific mortality rates positive for a time trend.