Trends in the incidence and mortality of ovarian cancer in Denmark 1978-2002. Comparison with other Nordic countries

Background. The Nordic countries are well-known high-incidence areas of ovarian cancer, but even within the Nordic countries, differences exist. Methods. Focus in this descriptive epidemiological study is to assess developments in incidence and mortality of ovarian cancer in Denmark 1978-2002 and to make a comparison with the development in the other Nordic countries. The results are based on data from the nationwide Danish Cancer Registry as well as the other Nordic Cancer Registries. Results. A total of 14 325 cases of ovarian cancer were registered from 1978 to 2002 in Denmark. In this period, the age-standardized incidence decreased slightly from 14.3 (1978-1982) to 13.3 per 100 000 woman-years (1998-2002). The histology-specific time trends showed a tendency towards more specified histological diagnoses. Iceland had the highest age-adjusted ovarian cancer incidence in the Nordic countries, whereas Denmark had the highest mortality rate. In the entire period, the Danish mortality rate declined from 10.8 (1978-1982) to 9.0 per 100 000 woman-years (1998-1999). Only 19% of ovarian cancers in Denmark from 1978 to 2002 were localized at the time of diagnosis, while 30% had distant metastases. Older women were more likely to have advanced disease at diagnosis. The Danish distribution of stage at diagnosis seems less favorable compared to results from other countries. Conclusions. The Danish incidence of ovarian cancer seemed to decrease slightly from 1978 to 2002. Even though the mortality rate of ovarian cancer also declined, Denmark had the highest mortality rate of ovarian cancer in the world. Part of it may be explained by a less-favorable distribution of stage at diagnosis.