Trends in the incidence of ovarian cancer and borderline tumours in Norway, 1954-1993.

Histology-specific long-term trends in the incidence of ovarian cancer and borderline tumours in Norway were examined, based on data from the population-based Cancer Registry of Norway. A total of 14,352 cases of ovarian cancer were diagnosed between 1954-1993, of which 94% of the histologically verified ovarian cancers were epithelial tumours. The age-adjusted incidence rate rose from 10 per 100,000 person-years in 1954-1958 to a peak of 14 per 100,000 person-years in 1984-1988. In women older than 50 years, there was an increasing trend in incidence rates during the entire study period. From the cohort perspective, the largest increase was observed among women born between 1870-1899. A total of 2,343 borderline tumours was diagnosed between 1970-1993. The age-adjusted incidence rate has increased since 1970, reaching 4.8 per 100,000 person-years in 1989-1993.